Semiconductor memory device and method for arranging and manufacturing the same

ABSTRACT

A semiconductor device and method for arranging and manufacturing the same are disclosed. The semiconductor device includes a plurality of inverters including at least one first pull-up transistor and first pull-down transistor and inverting and outputting an input signal, respectively; and a plurality of NAND gates including at least two second pull-up transistor and second pull-down transistor and generating an output signal having a high level if at least one of at least two input signals has a low level, respectively, wherein the at least one first pull-up transistor and first pull-down transistor and the at least two second pull-up transistor and second pull-down transistor are stacked and arranged on at least two layers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application Nos.2004-61527, filed Aug. 4, 2004, and 2005-38621, filed May 9, 2005, thedisclosures of which are hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to integrated circuit devices and, moreparticularly, to integrated circuit memory devices and methods ofmanufacturing integrated circuit memory devices.

BACKGROUND OF THE INVENTION

Conventional semiconductor memory devices may include a memory cellarray having a plurality of memory cells, which store data and aperipheral circuit which controls data input/output to/from the memorycell array. A static memory cell (e.g., SRAM cell) includes a pluralityof transistors, and a dynamic memory cell (e.g., DRAM cell) includes onetransistor and one capacitor. The peripheral circuit may include aninverter, a NAND gate and a NOR gate, where each of the gates includestransistors. In the typical memory cell and peripheral circuit, all of aplurality of transistors are arranged on the same layer above asemiconductor substrate. Thus, as the capacity of the memory cell array(i.e., the number of the memory cells) is increased, the layout areasize is also increased, which may lead to large chip size.

For the foregoing reason, research has been performed to reduce thelayout area size even as a capacity of the memory cell array isincreased. For example, a method of reducing layout area size of thememory cell array by stacking transistors in a memory cell has beenintroduced (see, e.g., FIGS. 5A and 6A).

However, if layout area size of the peripheral circuit as well as layoutarea size of the memory cell array is reduced, the total area size ofthe semiconductor memory device can be reduced as much. Besides, astransistors that form the memory cell are stacked, the transistors,which form the memory cell, should have different structure.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a semiconductormemory device which has a peripheral circuit suitable for a memory cellarray having stacked transistors.

It is another object of the present invention to provide methods forarranging and manufacturing a semiconductor memory device which has aperipheral circuit suitable for a memory cell array having stackedtransistors.

A first embodiment of the present invention includes a plurality ofinverters including at least one first pull-up transistor and firstpull-down transistor and inverting and outputting an input signal,respectively; and a plurality of NAND gates including at least twosecond pull-up transistor and second pull-down transistor and generatingan output signal having a high level if at least one of at least twoinput signals has a low level, respectively, wherein the at least onefirst pull-up transistor and first pull-down transistor and the at leasttwo second pull-up transistor and second pull-down transistor arestacked and arranged on at least two layers.

A second embodiment of a semiconductor device of the present inventionincludes a plurality of inverters including at least one first pull-uptransistor and first pull-down transistor and inverting and outputtingan input signal, respectively; a plurality of NAND gates including atleast two second pull-up transistor and second pull-down transistor andgenerating an output signal having a high level if at least one of atleast two input signals has a low level, respectively; and a pluralityof NOR gates including at least two third pull-up transistor and thirdpull-down transistor and generating an output signal having a high levelif all of at least two input signals have a low level, respectively,wherein the at least one first pull-up transistor and first pull-downtransistor, the at least two second pull-up transistor and secondpull-down transistor, and the at least two third pull-up transistor andthird pull-down transistor are stacked and arranged on at least twolayers.

In the first and second aspects of the semiconductor memory devices, thefirst to third pull-up transistors are PMOS transistors, and the firstto third pull-down transistors are NMOS transistors. In the first andsecond aspects of the semiconductor memory devices, a transistor to bearranged on a first layer is a bulk transistor, and a transistor to bearranged on a second or more layer is a thin film transistor. In thefirst and second aspects of the semiconductor memory devices, some ofthe first to third pull-up transistors and some of the first to thirdpull-down transistors are arranged together on the first layer. Only thefirst to third pull-up transistors or only the first to third pull-downtransistors are arranged on the second or more layer.

A third embodiment of a semiconductor memory device of the presentinvention includes a memory cell array including a plurality of memorycells which are accessed in response to a plurality of word lineselecting signals and a plurality of column selecting signals; a rowdecoder for decoding a row address to generate the plurality of wordline selecting signals; and a column decoder for decoding a columnaddress to generate the plurality of column selecting signals, whereinthe row (column) decoder includes a plurality of inverters, each of theplurality of inverters includes at least one pull-up transistor andpull-down transistor, the pull-up and pull-down transistors are stackedand arranged on at least two layers.

The column (row) decoder includes a plurality of inverters, each of theplurality of inverters includes at least one pull-up transistor andpull-down transistor, and the pull-up and pull-down transistors arestacked and arranged on at least two layers.

The plurality of memory cells include a plurality of NMOS transistors,and the plurality of NMOS transistors are stacked and arranged on the atleast two layers. The pull-up transistor is a PMOS transistor, and thepull-down transistor is an NMOS transistor. A transistor to be arrangedon a first layer is a bulk transistor, and a transistor to be arrangedon a second or more layer is a thin film transistor. Some of the pull-uptransistors and some of the pull-down transistors are arranged togetheron the first layer. Only the pull-up transistors or only the pull-downtransistors are arranged on the second or more layer.

A fourth embodiment of a semiconductor memory device of the presentinvention includes a memory cell array including a plurality of memorycells which are accessed in response to a plurality of word lineselecting signals and a plurality of column selecting signals; a rowdecoder for decoding a row address to generate the plurality of wordline selecting signals; and a column decoder for decoding a columnaddress to generate the plurality of column selecting signals, whereinthe row (column) decoder includes a plurality of inverters and aplurality of NAND gates, each of the plurality of inverters includes atleast one first pull-up transistor and first pull-down transistor, eachof the plurality of NAND gates includes at least two second pull-uptransistors and second pull-down transistors, and the first and secondpull-up transistors and the first and second pull-down transistors arestacked and arranged on at least two layers.

The column (row) decoder includes a plurality of inverters and aplurality of NAND gates, each of the plurality of inverters includes atleast one first pull-up transistor and first pull-down transistor, eachof the plurality of NAND gates includes at least two second pull-uptransistors and second pull-down transistors, the first and secondpull-up transistors and the first and second pull-down transistors arestacked and arranged on at least two layers.

The plurality of memory cells include a plurality of NMOS transistors,and the plurality of NMOS transistors are stacked and arranged on the atleast two layers. The first and second pull-up transistors are PMOStransistors, and the first and second pull-down transistors are NMOStransistors. A transistor to be arranged on a first layer is a bulktransistor, and a transistor to be arranged on a second or more layer isa thin film transistor. Some of the first and second pull-up transistorsand some of the first and second pull-down transistors are arrangedtogether on the first layer. Only the first and second pull-uptransistors or only the first and second pull-down transistors arearranged on the second or more layer.

A fifth embodiment of a semiconductor memory device of the presentinvention includes a memory cell array including a plurality of memorycells which are accessed in response to a plurality of word lineselecting signals and a plurality of column selecting signals; and aperipheral circuit including a row decoder for decoding a row address togenerate the plurality of word line selecting signals, a column decoderfor decoding a column address to generate the plurality of columnselecting signals, and a controller for controlling input/output of datato/from the memory cell array, wherein the peripheral circuit includes aplurality of inverters, a plurality of NAND gates, and a plurality ofNOR gates, each of the plurality of inverters includes at least onefirst pull-up transistor and first pull-down transistor, each of theplurality of NAND gates includes at least two second pull-up transistorsand second pull-down transistors, each of the plurality of NOR gatesincludes at least three third pull-up transistors and third pull-downtransistors, and the first to third pull-up transistors and the first tothird pull-down transistors are stacked and arranged on at least twolayers.

The plurality of memory cells include a plurality of NMOS transistors,and the plurality of NMOS transistors are stacked and arranged on the atleast two layers. The first to third pull-up transistors are PMOStransistors, and the first to third pull-down transistors are NMOStransistors. A transistor to be arranged on a first layer is a bulktransistor, and a transistor to be arranged on a second or more layer isa thin film transistor. Some of the first to third pull-up transistorsand some of the first to third pull-down transistors are arrangedtogether on the first layer. Only the first to third pull-up transistorsor only the first to third pull-down transistors are arranged on thesecond or more layer.

A sixth embodiment of a semiconductor device includes a semiconductorsubstrate having a cell region and a peripheral circuit region; bulktransistors arranged on the semiconductor substrate of the cell region;an interlayer insulator pattern arranged in the cell region to cover thebulk transistors; thin film transistors arranged on the interlayerinsulator pattern; a peripheral body pattern arranged to contact thesemiconductor substrate of the peripheral circuit region; and peripheraltransistors arranged in the peripheral body pattern, the peripheraltransistors arranged to be located on the substantially same imaginaryhorizontal line as the thin film transistors of the cell region. Theperipheral body pattern is a single crystal semiconductor structure. Thethin film transistors are single crystal thin film transistors. The bulktransistors and the thin film transistors are cell transistors of anSRAM memory cell.

The bulk transistors include first and second bulk transistors, the thinfilm transistors include first and second thin film transistors, and thefirst and second thin film transistors are arranged to respectivelyoverlap the first and second bulk transistors. The semiconductor devicefurther includes first and second lower thin film transistorsrespectively arranged between the first and second bulk transistors andthe first and second thin film transistors, wherein the first and secondlower thin film transistors are arranged to respectively overlap thefirst and second bulk transistors.

The semiconductor device further includes a first node plug forelectrically connecting a first ion-doped region of the first bulktransistor, a first ion-doped region of the first lower thin filmtransistor, and a first ion-doped region of the first upper thin filmtransistor through the interlayer insulator; and a second node plug forelectrically connecting a first ion-doped region of the second bulktransistor, a first ion-doped region of the second lower thin filmtransistor, and a first ion-doped region of the second upper thin filmtransistor through the interlayer insulator. The first and second bulktransistors are first and second n-channel driving transistors,respectively, and the first ion-doped regions of the first and secondbulk transistors are drain regions. A gate electrode of the firstdriving transistor is electrically connected to the second node plug,and a gate of the second driving transistor is electrically connected tothe first node plug.

The first and second lower thin film transistors are respectively firstand second p-channel load transistors, the first and second thin filmtransistors are first and second n-channel transmission transistors, thefirst ion-doped regions of the first and second lower thin filmtransistors are drain regions, and the first ion-doped regions of thefirst and second thin film transistors are source regions. Gateelectrodes of the first and second load transistors are arranged tooverlap gate electrodes of the first and second driving transistors, thegate electrode of the first load transistor is electrically connected tothe second node plug, and the gate electrode of the second loadtransistor is electrically connected to the first node plug. Gateelectrodes of the first and second thin film transistors areelectrically connected to each other to form a word line. At least theperipheral transistor includes a metal silicide layer arranged on asurface of a peripheral gate electrode. At least the peripheraltransistor includes a metal silicide layer arranged on surfaces ofperipheral source and drain regions.

A first aspect of an arrangement method of a semiconductor memory deviceaccording to the present invention includes stacking and arranging twotransmission transistors, two first pull-up transistors, two firstpull-down transistors which constitute each of a plurality of memorycells of a memory cell array on at least two layers; and stacking andarranging at least one second pull-up transistors and second pull-downtransistors which constitute each of a plurality of inverters of aperipheral circuit and at least two third pull-up transistors and thirdpull-down transistors which constitute each of a plurality of NAND gateson the least two layers.

The first to third pull-up transistors are PMOS transistors, and thefirst to third pull-down transistors are NMOS transistors. A transistorto be arranged on a first layer is a bulk transistor, and a transistorto be arranged on a second or more layer is a thin film transistor.

A transistor to be arranged on the first layer among the at least twolayers of the peripheral circuit is one which is possible to be arrangedtogether with some of the second and third pull-up transistors and thesecond and third pull-down transistors regardless of a type of atransistor to be arranged on the first layer of the memory cell array.Only the second and third pull-up transistors or only the second andthird pull-won transistors which have the same type as transistors whichare respectively arranged on a second or more layer of the at least twolayers of the peripheral circuit are arranged.

A second aspect of an arrangement method of a semiconductor memorydevice according to the present invention includes stacking andarranging two transmission transistors, two first pull-up transistors,two first pull-down transistors which constitute each of a plurality ofmemory cells of a memory cell array on at least two layers; and stackingand arranging at least one second pull-up transistors and secondpull-down transistors which constitute each of a plurality of invertersof a peripheral circuit, at least two third pull-up transistors andthird pull-down transistors which constitute each of a plurality of NANDgates, and at least two fourth pull-up transistors and fourth pull-downtransistors which constitute each of a plurality of NOR gates on theleast two layers.

The first to fourth pull-up transistors are PMOS transistors, and thefirst to third pull-down transistors are NMOS transistors. A transistorto be arranged on a first layer is a bulk transistor, and a transistorto be arranged on a second or more layer is a thin film transistor.

A transistor to be arranged on the first layer among the at least twolayers of the peripheral circuit is one which is possible to be arrangedtogether with some of the second to fourth pull-up transistors and thesecond to fourth pull-down transistors regardless of a type of atransistor to be arranged on the first layer of the memory cell array.Only the second to fourth pull-up transistors or only the second tofourth pull-won transistors which have the same type as transistorswhich are respectively arranged on a second or more layer of the atleast two layers of the peripheral circuit are arranged.

A first aspect of a method of manufacturing a semiconductor deviceincludes preparing a semiconductor substrate having a cell region and aperipheral circuit region; forming a bulk transistor on thesemiconductor substrate of the cell region; forming an interlayerinsulator pattern which exposes the semiconductor substrate of theperipheral circuit region on the semiconductor substrate having the bulktransistor; forming a cell body pattern and a peripheral body pattern onthe interlayer insulator pattern and the exposed portion of thesemiconductor substrate, wherein the peripheral body pattern contactsthe exposed portion of the semiconductor substrate; and forming a cellthin film transistor and a peripheral transistor in the cell bodypattern and the peripheral body pattern, respectively.

The step of forming the cell body pattern and the peripheral bodypattern includes forming a semiconductor layer on the semiconductorsubstrate having the interlayer insulator pattern; and planarizing thesemiconductor layer to form a cell semiconductor layer and a peripheralsemiconductor layer on the interlayer insulator pattern and thesemiconductor substrate of the peripheral circuit region, wherein theperipheral semiconductor layer is thicker than the semiconductor layer.The semiconductor layer is formed of a non-single crystal semiconductorlayer.

The method of the first aspect further includes crystallizing thesemiconductor layer using a solid phase epitaxial layer which employsthe semiconductor substrate as a seed layer before or after planarizingthe semiconductor layer. The step of forming the interlayer insulatorpattern includes forming an interlayer insulator on the semiconductorsubstrate having the bulk transistor; and patterning the interlayerinsulator to form a contact hole which exposes the semiconductorsubstrate of the peripheral circuit region and a predetermined region ofthe semiconductor substrate of the cell region.

The step of forming the cell body pattern and the peripheral bodypattern includes forming a single crystal semiconductor structure on theinterlayer insulator pattern and the exposed portion of thesemiconductor substrate of the peripheral circuit region; andplanarizing the single crystal semiconductor structure.

The single crystal semiconductor structure is formed by using aselective epitaxial growth technique which employs the semiconductorsubstrate exposed by the contact hole and the exposed semiconductorsubstrate of the peripheral circuit region as a seed layer. The step offorming the cell thin film transistor and the peripheral transistorincludes a cell gate electrode and a peripheral gate electrode whichrespectively cross the cell body pattern and the peripheral bodypattern; ion-doping the cell body pattern and the peripheral bodypattern using the gate electrodes as an ion-doping mask to form cellsource and drain regions in the cell body pattern and peripheral sourceand drain regions in the peripheral body pattern. The method of thefirst aspect further includes forming selectively a metal silicide layeron surfaces of the peripheral gate electrode and/or the peripheralsource and drain regions.

A second aspect of a method of manufacturing a semiconductor deviceincludes preparing a semiconductor substrate having a cell region and aperipheral circuit region; forming a bulk transistor on thesemiconductor substrate of the cell region; forming a first interlayerinsulator pattern which exposes the semiconductor substrate of theperipheral circuit region on the semiconductor substrate having the bulktransistor, the first interlayer insulator pattern having a firstcontact hole which exposes a predetermined region of an ion-doped regionof the bulk transistor; forming a cell lower body pattern for coveringthe first contact hole on the first interlayer insulator pattern;forming a cell lower thin film transistor in the cell lower bodypattern; forming a second interlayer insulator pattern for covering thecell lower thin film transistor on the first interlayer insulatorpattern, the second interlayer insulator pattern having a second contacthole which exposes a predetermined region of an ion-doped region of thecell lower thin film transistor; forming a cell upper body pattern forcovering the second contact hole on the second interlayer insulatorpattern and a peripheral body pattern in the peripheral circuit region;and forming a cell upper thin film transistor in the cell upper bodypattern and a peripheral transistor in the peripheral body pattern.

The method of the second aspect further includes forming the cell lowerbody pattern and a peripheral body pattern for covering thesemiconductor substrate of the peripheral circuit region. The step offorming the cell lower body pattern and the peripheral lower bodypattern includes forming a first single crystal semiconductor structurewhich fills the first contact hole and covers the first interlayerinsulator pattern and the semiconductor substrate of the peripheralcircuit region; and planarizing the first single crystal semiconductorstructure.

The step of forming the cell upper body pattern and the peripheral bodypattern includes forming a second single crystal semiconductor structurewhich fills the second contact hole and covers the second interlayerinsulator pattern and the semiconductor substrate of the peripheralcircuit region; planarizing the second single crystal semiconductorstructure; and patterning the second single crystal semiconductorstructure to form a cell upper body pattern in the cell region and aperipheral upper body pattern in the peripheral circuit region, therebyforming a peripheral body pattern having the peripheral lower bodypattern and the peripheral upper body pattern. The single crystalsemiconductor structures are formed by using an epitaxial technique.

The step of forming the cell lower body pattern includes forming a firstsingle crystal semiconductor structure which fills the first contacthole and covers the first interlayer insulator pattern and thesemiconductor substrate of the peripheral circuit region; and patterningthe first single crystal semiconductor structure to expose thesemiconductor substrate of the peripheral circuit region.

The step of forming the cell upper body pattern and the peripheral bodypattern includes forming a second single crystal semiconductor structurewhich fills the second contact hole and covers the second interlayerinsulator pattern and the semiconductor substrate of the peripheralcircuit region, the second single crystal semiconductor structure havinga plane upper surface; and patterning the second single crystalsemiconductor structure to form the cell upper body pattern in the cellregion and the peripheral body pattern in the peripheral circuit region.The single crystal semiconductor structures are formed by using anepitaxial technique.

The bulk transistor is an n-channel driving transistor, the cell lowerthin film transistor is a p-channel load transistor, and the cell upperthin film transistor is an n-channel transmission transistor. The stepof forming the cell upper thin film transistor and the peripheraltransistor includes forming a cell upper gate electrode and a peripheralgate electrode which respectively cross the cell upper body pattern andthe peripheral body pattern; and ion-doping the cell upper body patternand the peripheral body pattern using the gate electrode as an iondoping mask to form cell source and drain regions in the cell upper bodypattern and peripheral source and drain regions in the peripheral bodypattern. The method of the second aspect further includes formingselectively a metal silicide layer on surfaces of the peripheral gateelectrode and/or the peripheral source and drain regions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a typical semiconductor memorydevice;

FIG. 2 is a block diagram illustrating a row decoder or a column decoderof the semiconductor memory device of FIG. 1;

FIGS. 3A to 3D are circuit diagrams illustrating a static memory cell ofa memory cell array, and an inverter, a NAND gate, and a NOR gate whichconstitute a peripheral circuit in the conventional semiconductor memorydevice;

FIGS. 4A-4D illustrate an arrangement of transistors which constitutethe static memory cell and transistors which constitute the inverter,the NAND gate and the NOR gate in the conventional semiconductor memorydevice;

FIGS. 5A to 5D are views respectively illustrating different arrangementof transistors of the static memory cell and transistors whichconstitute the inverter, the NAND gate and the NOR gate of theperipheral circuit in the conventional semiconductor memory device;

FIGS. 6A to 6D are views respectively illustrating another differentarrangement of transistors of the static memory cell and transistorswhich constitute the inverter, the NAND gate and the NOR gate of theperipheral circuit in the conventional semiconductor memory device;

FIGS. 7A to 7D are views respectively illustrating arrangement oftransistors of a static memory cell and transistors which constitute aninverter, a NAND gate and a NOR gate of a peripheral circuit of asemiconductor memory device according to a first embodiment of thepresent invention;

FIGS. 8A to 8D are views respectively illustrating arrangement oftransistors of a static memory cell and transistors which constitute aninverter, a NAND gate and a NOR gate of a peripheral circuit of asemiconductor memory device according to a second embodiment of thepresent invention;

FIGS. 9A to 9D are views respectively illustrating arrangement oftransistors of a static memory cell and transistors which constitute aninverter, a NAND gate and a NOR gate of a peripheral circuit of asemiconductor memory device according to a third embodiment of thepresent invention;

FIGS. 10A to 16D are plane views illustrating respective arrangement ofthe memory cell, the inverter, the NAND gate, and the NOR gate accordingto an embodiment of the present invention;

FIGS. 17A and 17B are cross-sectional views respectively taken alongline I-I′ and II-II′ of FIG. 16A, illustrating structure of the memorycell according to the embodiment of the present invention;

FIGS. 18 to 20 are cross-sectional views taken along line X-X′ of FIGS.10B to 16B, FIGS. 10C to 16C, and FIGS. 10D to 16D, illustrating thestructure of the memory cell according to the embodiment of the presentinvention;

FIGS. 21A and 21B are views illustrating stacking structure of thememory cell array and the peripheral circuit according to a firstembodiment of the present invention;

FIGS. 22A and 22B are views illustrating stacking structure of thememory cell array and the peripheral circuit according to a secondembodiment of the present invention;

FIGS. 23A and 23B are views illustrating stacking structure of thememory cell array and the peripheral circuit according to a thirdembodiment of the present invention;

FIGS. 24A and 24B are views respectively illustrating arrangement oftransistors of a static memory cell and transistors which constitute aninverter of a peripheral circuit of a semiconductor memory deviceaccording to a fourth embodiment of the present invention;

FIG. 25 is a plan view illustrating the inverter of the peripheralcircuit of FIG. 24B; and

FIGS. 26A and 26B to FIGS. 34A and 34B are cross-sectional viewsillustrating a method for manufacturing the memory cell and theinverter.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, the thickness of layers and regions are exaggerated forclarity. Like numbers refer to like elements throughout thespecification.

FIG. 1 is a block diagram illustrating a typical semiconductor memorydevice. The semiconductor memory device of FIG. 1 includes a memory cellarray 10, a row decoder 12, a data I/O gate 14, a column decoder 16, adata I/O circuit 18, and a controller 20. In FIG. 1, wl1 to wlm denoteword line selecting signals, y1 to yn denote column selecting signals,WL1 to WLm denote word lines, and BL1,BL1B to BLn,BLnB denote bit linepairs. Functions of components of the semiconductor memory device ofFIG. 1 will be described below.

The memory cell array 10 includes a plurality of static memory cellsMC11 to MCmn respectively connected between each of the word lines WL1to WLm and each of the bit line pairs BL1,BL1B to BLn,BLnB, receivesdata din and writes it onto a selected memory cell during writeoperations, and reads data stored in a selected memory cell and outputsthe data dout during read operations. The row decoder 12 decodes a rowaddress RA to generate the word line selecting signals wl1 to wlm inresponse to an active command ACT. The data I/O gate 14 transmits dataDin as data din during the write operations and transmits data dout asdata Dout during the read operations, in response to the columnselecting signals y1 to yn. The column decoder 16 decodes a columnaddress CA to generate the column selecting signals y1 to yn, inresponse to read and write commands RD, WR. The data I/O circuit 18receives data DIN and outputs data Din in response to the write commandWR, and receives data Dout and outputs data DOUT in response to the readcommand RD. The controller 20 receives a command COM to generate theactive command ACT, the read command RD, and the write command WR.

FIG. 2 is a block diagram illustrating the row decoder or the columndecoder of the semiconductor memory device of FIG. 1. The decoder ofFIG. 2 includes two pre-decoders 30 and 32 and a main decoder 34. Thetwo pre-decoders 30 and 32 and the main decoder 34 include a two-inputNAND gate NA and an inverter INV, respectively. The decoder of FIG. 2 isconfigured to receive 4-bit address A1 to A4 to generate 16 decodingsignals DRA1 to DRA16. Functions of components of the decoder of FIG. 2will be explained below.

Each of the pre-decoders 30 and 32 decodes two 2-bit addresses A1,A2 andA3,A4 to output pre-decoded signals DRA1B2B to DRA12 and DRA3B4B toDRA34. The main decoder 34 decodes the pre-decoded signals DRA1B2B toDRA12 and DRA3B4B to DRA34 to generate decoding signals DRA1 to DRA16.The static memory cell of the memory cell array of the semiconductormemory device includes six (6) transistors, and the column or rowdecoder includes logic gates such as an inverter and a NAND gate. Theinverter includes two transistors, and the NAND gate includes at least 4transistors. The column or row decoder of FIG. 2 includes the two-inputNAND gate and thus is comprised of four transistors, but in case wherethe decoder of FIG. 2 includes a 3- or 4-input NAND gate, it iscomprised of 6 or 8 transistors. The data I/O circuit 18 and thecontroller 20 further includes a NOR gate in addition to the inverterand the NAND gate.

FIG. 3A is a circuit diagram illustrating the static memory cell of thememory cell array of FIG. 1. FIGS. 3B to 3D are circuit diagramsrespectively illustrating an inverter, a NAND gate, and a NOR gate whichconstitute the peripheral circuit. As shown in FIG. 3A, the staticmemory cell includes PMOS transistors PU1 and PU2 and NMOS transistorsPD1, PD2, T1, and T2. The PMOS transistors PU1 and PU2 are pull-uptransistors, and the NMOS transistors are pull-down transistors, and theNMOS transistors T1 and T2 are transmission transistors. Operation ofthe static memory cell of FIG. 3A will be described below.

If the word line WL is selected so that the NMOS transistors T1 and T2are turned on, data is transmitted between the bit line BL and thestorage node a, and data is transmitted between an inverted bit line BLBand a storage node b. If data of the storage node b has a high level,the NMOS transistor PD1 makes the storage node a have a low level, andif data of the storage node b has a low level, the PMOS transistor PU1makes the storage node a have a high level. Likewise, if data of thestorage node a has a high level, the NMOS transistor PD2 makes thestorage node b have a low level, and if data of the storage node a has alow level, the PMOS transistor PU2 makes the storage node b have a highlevel. That is, the two PMOS transistors PU1 and PU2 and the two NMOStransistors PD1 and PD2 serve as a latch and latches data of the storagenodes a and b.

As shown in FIG. 3B, the inverter includes a PMOS transistor P1 and anNMOS transistor N1. In FIG. 3B, the PMOS transistor P1 is a pull-uptransistor, and the NMOS transistor N1 is a pull-down transistor.Operation of the inverter of FIG. 3B is as follows. If an input signalIN having a high level is inputted, the NMOS transistor N1 is turned onto make an output signal OUT have a low level, i.e., a ground voltageVss level. On the other hand, if an input signal IN having a low levelis inputted, the PMOS transistor P1 is turned on to make the outputsignal OUT have a high level, i.e., a power voltage Vcc level. That is,the inverter of FIG. 3B is comprised of one pull-up transistor and onepull-down transistor and inverts an input signal IN to generate theoutput signal OUT.

As shown in FIG. 3C, the NAND gate includes PMOS transistors P2 and P3and NMOS transistors N2 and N3. In FIG. 3C, the PMOS transistors P2 andP3 are pull-up transistors, and the NMOS transistors N2 and N3 arepull-down transistors. Operation of the NAND gate of FIG. 3C is asfollows. If at least one of input signals IN1 and IN2 having a low levelis applied, the PMOS transistor P2 and/or the PMOS transistor P3 are/isturned on to make an output signal OUT have a high level, i.e., a powervoltage Vcc level. On the other hand, if the input signals IN1 and IN2having a high level are applied, the NMOS transistors N2 and N3 areturned on to make the output signal OUT have a low level.

As shown in FIG. 3D, the NOR gate includes PMOS transistors P4 and P5and NMOS transistors N4 and N5. In FIG. 3D, the PMOS transistors P3 andP4 are pull-up transistors, and the NMOS transistors are pull-downtransistors. Operation of the NOR gate of FIG. 3D is as follows. If atleast one of input signals IN1 and IN2 having a high level is applied,the NMOS transistor N4 and/or the NMOS transistor N5 are/or turned on tomake an output signal OUT have a low level, i.e., a ground voltage Vsslevel. On the other hand, if input signals IN1 and IN2 having a lowlevel are applied, the PMOS transistors P4 and P5 are turned on to makethe output signal OUT have a high level.

FIG. 4A is a view illustrating arrangement of the transistors whichconstitute the static memory cell of FIG. 3A, and FIGS. 4B to 4D areviews respectively illustrating arrangement of the transistors whichconstitute the inverter, the NAND gate and the NOR gate shown in FIGS.3B to 3D. In FIGS. 4A to 4D, it appears that a bit line pair BL and BLB,a word line WL, a power voltage line VCCL, and a ground voltage lineVSSL are arranged on difference layers, but they are not always arrangedon difference layers.

As shown in FIG. 4A, the transistors PD1, PD2, PU1, PU2, T1, and T2 ofFIG. 3A are arranged on the same layer 1F. A source of the NMOStransistor T1 is connected to a drain of the NMOS transistor PD1, asource of the NMOS transistor PD1 is connected to a source of the NMOStransistor PD2, and a drain of the NMOS transistor PD2 is connected to asource of the NMOS transistor T2. A drain of the NMOS transistor T1 isconnected to a bit line BL, a drain of the NMOS transistor T2 isconnected to an inverted bit line BLB, gates of the NMOS transistors T1and T2 are connected to the word line, and sources of the NMOStransistors PD1 and PD2 are connected to the ground voltage line VSSL. Adrain of the PMOS transistor PU1 is connected to a source of the NMOStransistor PD1, a source of the PMOS transistor PU1 is connected to thepower voltage line VCCL, and a gate of the PMOS transistor PU1 isconnected to a gate of the NMOS transistor PD1 and a drain of the NMOStransistor PD2. A drain of the PMOS transistor PU2 is connected to adrain of the NMOS transistor PD2, a source of the PMOS transistor PU2 isconnected to the power voltage line VCCL, and a gate of the PMOStransistor PU2 is connected to a gate of the NMOS transistor PD2.

As shown in FIG. 4B, the transistors P1 and N1 of FIG. 3B are arrangedon the same floor 1F. The PMOS transistor P1 has a source connected tothe power voltage line VCCL, a drain connected to an output signal lineOUTL, and a gate connected to an input signal line INL. The NMOStransistor N1 has a source connected to the ground voltage line VSSL, adrain connected to the output signal line OUTL, and a gate connected tothe input signal line INL.

As shown in FIG. 4C, the transistors P2, P3, N2 and N3 of FIG. 3C arearranged on the same layer 1F. A source of the PMOS transistor P3 isconnected to a source of the PMOS transistor P2, and a drain of the PMOStransistor P3 is connected to the output signal line OUTL. Gates of thePMOS transistor P3 and the NMOS transistor N3 are connected to an inputsignal line IN1L, gates of the PMOS transistor P2 and the NMOStransistor N2 are connected to an input signal line IN2L, drains of thePMOS transistor P2 and the NMOS transistor N2 are connected, sources ofthe NMOS transistors N2 and N3 are connected, and a drain of the NMOStransistor N3 is connected to the ground voltage line VSSL.

As shown in FIG. 4D, the transistors P4, P5, N4, and N5 of FIG. 3D arearranged on the same layer 1F. A drain of the PMOS transistor P4 isconnected to a source of the PMOS transistor P5, a drain of the PMOStransistor P5 is connected to a drain of the NMOS transistor N5, asource and a gate of the PMOS transistor P4 are respectively connectedto the power voltage line VCCL and the input signal line IN2L, a gate ofthe PMOS transistor P5 is connected to the input signal line IN1L,drains of the PMOS transistor P5 and the NMOS transistor N5 areconnected to the output signal line OUTL, and a drain, a gate and asource of the NMOS transistor N4 are respectively connected to theoutput signal line OUTL, the input signal line IN2L and the groundvoltage line VSSL.

As shown in FIGS. 4A to 4D, all of the transistors which constitute thememory cell and the peripheral circuit of the conventional semiconductormemory device are arranged on the same layer 1F, and thus in case wherecapacitor of the memory cell is increased, layout area size is alsoincreased.

In order to reduce the layout area size of the memory cell of thesemiconductor memory device, a method of arranging transistors, whichconstitute the memory cell on two or three layers has been introduced.FIGS. 5A to 5D are views respectively illustrating differentarrangements of the transistors of the static memory cell and thetransistors which constitute the inverter, the NAND gate and the NORgate of the peripheral circuit in the conventional semiconductor memorydevice, where the transistors which constitute the memory cell arearranged on two layers.

As shown in FIG. 5A, the NMOS transistors PD1, PD2, T1, and T2 arearranged on a first layer 1F, and the PMOS transistors PU1 and PU2 arearranged on a second layer 2F. Connections between the transistors PD1,PD2, PU1, PU2, T1, and T2 are identical to those of FIG. 4A. Likearrangement of FIGS. 4B to 4D, the transistors P1 to P5 and N1 to N5 ofFIGS. 5B to 5D which constitute the inverter, the NAND gate and the NORgate are arranged on the first layer 1F. Therefore, as shown in FIG. 5A,if the transistors which constitute the memory cell are arranged on thetwo layers and the transistors which constitute the peripheral circuitare on one layer, the layout area size of the memory cell array isreduced, but the layout area size of the peripheral circuit is notreduced.

FIGS. 6A to 6D are views respectively illustrating another differentarrangement of the transistors of the static memory cell and thetransistors which constitute the inverter, the NAND gate and the NORgate of the peripheral circuit in the conventional semiconductor memorydevice, where the transistors which constitute the memory cell arearranged on three layers.

As shown in FIG. 6A, the NMOS transistors PD1 and PD2 are arranged on afirst layer 1F, the PMOS transistors PU1 and PU2 are arranged on asecond layer 2F, and the access transistors T1 and T2 are arranged on athird layer 3F. Connections between the transistors PD1, PD2, PU1, PU2,T1, and T2 are identical to those of FIG. 4A.

Like the arrangement of FIGS. 4B to 4D, the transistors P1 to P5 and N1to N5 of FIGS. 6B to 6D which constitute the inverter, the NAND gate andthe NOR gate are arranged on the first layer 1F. Therefore, as shown inFIG. 6A, if the transistors which constitute the memory cell arearranged on the three layers and the transistors which constitute theperipheral circuit are on one layer, the layout area size of the memorycell array is reduced, but the layout area size of the peripheralcircuit is not reduced. In the conventional arrangement of thesemiconductor memory device, the layout area size of the memory cellarray is reduced by arranging the transistors, which constitute thestatic memory cell on two or three layers, but since the transistors,which constitute the peripheral circuit, are arranged on one layer, thelayout area size of the peripheral circuit is not reduced.

FIGS. 7A to 7D are views respectively illustrating arrangement oftransistors of a static memory cell and transistors which constitute aninverter, a NAND gate and a NOR gate of a peripheral circuit of asemiconductor memory device according to a first embodiment of thepresent invention. In particular, FIGS. 7A to 7D show arrangement oftransistors which constitute the peripheral circuit in case wheretransistors which constitute the memory cell are arranged on two layers.

Like arrangement of FIG. 5A, transistors PD1, PD2, PU1, PU2, T1, and T2of FIG. 7A that constitute the static memory cell are arranged on twolayers. As shown in FIG. 7B, an NMOS transistors N1 is arranged on thefirst layer 1F, and a PMOS transistor P1 is arranged on the second layer2F. Connection between the transistors N1 and P1, which constitute theinverter, are identical to those of FIG. 4B. As shown in FIG. 7C, NMOStransistors N2 and N3 are arranged on the first layer 1F, and PMOStransistors P2 and P3 are arranged on the second layer 2F. Connectionsbetween the transistors N2, N3, P2, and P3, which constitute the NANDgate, are identical to those of FIG. 4C. As shown in FIG. 7D, NMOStransistors N4 and N4 are arranged on the first layer 1F, and PMOStransistors P4 and P5 are arranged on the second layer 2F. Connectionsbetween the transistors N4, N5, P4, and P5 which constitute the NOR gateare identical to those of FIG. 4D. As shown in FIGS. 7A to 7D, thesemiconductor memory device of the present invention can reduce thelayout area size by arranging the transistors which constitute thememory cell on two layers and arranging the transistors which constitutethe peripheral circuit on two layers. The transistors of FIGS. 7B to 7Dmay be arranged on different layers from those shown in FIGS. 7A to 7D.For example, the transistors do not need to be always arranged on thefirst and second layers and may be arranged on the first and thirdlayers or the second and third layers.

However, the PMOS transistor and the NMOS transistor may be arranged onthe first layer, but it is preferred to arrange the same type transistoron the second layer 2F as the transistor arranged on the second layer ofthe memory cell for the convenience of manufacturing process. Forexample, it is preferable to arrange the NMOS transistor which is to bearranged on the second layer 2F of the peripheral circuit if thetransistors to be arranged on the second layer 2F of the memory cell areNMOS transistors, and it is preferable to arrange the PMOS transistorwhich is to be arranged on the second layer 2F of the peripheral circuitif the transistors to be arranged on the second layer 2F of the memorycell are PMOS transistors.

FIGS. 8A to 8D are views respectively illustrating arrangement oftransistors of a static memory cell and transistors which constitute aninverter, a NAND gate and a NOR gate of a peripheral circuit of asemiconductor memory device according to a second embodiment of thepresent invention. In particular, FIGS. 8A to 8D show arrangement oftransistors which constitute the peripheral circuit in case wheretransistors which constitute the memory cell are arranged on threelayers. Like arrangement of FIG. 6A, the transistors of FIG. 8A, whichconstitute the static memory cell, are arranged such that the pull-downtransistors PD1 and PD2 are arranged on the first layer 1F, the pull-uptransistors PU1 and PU2 are arranged on the second layer 2F, and thetransmission transistors T1 and T2 are arranged on the third layer. Asshown in FIG. 8B, NMOS transistors N1-1 and N1-2, which have ½ channelwidth of channel width of the NMOS transistor N1 of FIG. 3B arearranged. The NMOS transistor N1-2 is arranged on the first layer 1F,the PMOS transistor P1 is arranged on the second layer 2F, and the NMOStransistor N1-1 is arranged on the third layer 3F. Gates, drains andsources of the NMOS transistors N1-1 and N1-2 are commonly connected,and connections between the NMOS transistors N1-1 and N1-2 and the PMOStransistor P1 are identical to those of FIG. 4B.

As shown in FIG. 8C, a PMOS transistor P2 and an NMOS transistor N2 arearranged on the first layer 1F, the PMOS transistor P3 is arranged onthe second layer 2F, and an NMOS transistor N3 is arranged on the thirdlayer 3F. Connections between the PMOS transistors P2 and P3 and theNMOS transistors N2 and N3 are identical to those of FIG. 4C.

As shown in FIG. 8D, NMOS transistors N4-1 and N4-2 which have ½ channelwidth of channel width of the NMOS transistor N4 and NMOS transistorsN5-1 and N5-2 which have ½ channel width of channel width of the NMOStransistor N5 are arranged. The NMOS transistors N4-1 and N5-1 arearranged on the first layer 1F, PMOS transistors P4 and P5 are arrangedon the second layer 2F, and the NMOS transistors N5-1 and N5-2 arearranged on the third layer 3F. Gates, sources and drains of the NMOStransistors N4-1 and N4-2 are commonly connected, and Gates, sources anddrains of the NMOS transistors N5-1 and N5-2 are commonly connected.Connections between the PMOS transistors P4 and P5 and the NMOStransistors N4 and N5 are identical to those of FIG. 4D.

As shown in FIGS. 8A and 8D, the semiconductor memory device of thepresent invention can reduce the layout area size by arranging thetransistors which constitute the memory cell on three layers andarranging the transistors which constitute the peripheral circuit onthree layers.

FIGS. 9A to 9D are views respectively illustrating the arrangement oftransistors of a static memory cell and transistors which constitute aninverter, a NAND gate and a NOR gate of a peripheral circuit of asemiconductor memory device according to a third embodiment of thepresent invention. In particular, FIGS. 9A to 9D show arrangement oftransistors which constitute the peripheral circuit in case wheretransistors which constitute the memory cell are arranged on threelayers. Like the arrangement of FIG. 8A, the transistors of FIG. 9A,which constitute the static memory cell, are arranged on three layers.

As shown in FIG. 9B, PMOS transistors P1-1 and P1-2 which have ½ channelwidth of channel width of the PMOS transistor P1 which constitutes theinverter are arranged. The PMOS transistor P1-1 is arranged on the firstlayer 1F, the PMOS transistor P1-2 is arranged on the second layer 2F,and the NMOS transistor N1 is arranged on the third layer 3F. Gates,drains and sources of the PMOS transistors P1-1 and P1-2 are commonlyconnected, and connections between the PMOS transistors P1-1 and P1-2and the NMOS transistor N1 are identical to those of FIG. 4B.

As shown in FIG. 9C, the PMOS transistors P2-1 and P2-2 and the PMOStransistors P3-1 and P3-2 which respectively have ½ channel width ofrespective channel width of the PMOS transistors P2 and P3 whichconstitute the NAND gate are arranged. The PMOS transistors P2-2 andP3-2 are arranged on the first layer 1F, the PMOS transistors P2-1 andP3-1 are arranged on the second layer 2F, and the NMOS transistors N2and N3 are arranged on the third layer 3F. Gates, drains and sources ofthe PMOS transistors P2-1 and P2-2 are commonly connected, and gates,drains and sources of the PMOS transistors P3-1 and P3-2 are commonlyconnected, and connections between the PMOS transistors P2-1, P2-2,P3-1, and P3-2 and the NMOS transistors N2 and N3 are identical to thoseof FIG. 4C.

As shown in FIG. 9D, the PMOS transistors P4-1 and P4-2 and the PMOStransistors P5-1 and P5-2 which respectively have ½ channel width ofrespective channel width of the PMOS transistor P4 and P5 whichconstitute the NOR gate are arranged. The PMOS transistors P4-1 and P5-1are arranged on the first layer 1F, the PMOS transistors P4-2 and P5-2are arranged on the second layer 2F, and the NMOS transistors N4 and N5are arranged on the third layer 3F. Gates, drains and sources of thePMOS transistors P4-1 and P4-2 are commonly connected, and gates, drainsand sources of the PMOS transistors P5-1 and P5-2 are commonlyconnected, and connections between the PMOS transistors P4-1, P4-2,P5-1, and P5-2 and the NMOS transistors N4 and N5 are identical to thoseof FIG. 4D.

The PMOS transistor and the NMOS transistor may be arranged on the firstlayer, but it is preferred to arrange the same type transistor on thesecond layer 2F as the transistor arranged on the second layer of thememory cell for the convenience of manufacturing process. For example,it is preferable to arrange the PMOS transistor which is to be arrangedon the second layer 2F of the peripheral circuit if the transistors tobe arranged on the second layer 2F of the memory cell are PMOStransistors, and it is preferable to arrange the NMOS transistor whichis to be arranged on the third layer 3F of the peripheral circuit if thetransistors to be arranged on the third layer 3F of the memory cell areNMOS transistors.

Arrangement and structure of the inverter, the NAND gate, and the NORgate which constitute the static memory cell and the peripheral circuitaccording to an embodiment of the present invention will be explainedbelow.

FIGS. 10A to 16D are plan views illustrating respective arrangement ofthe memory cell, the inverter, the NAND gate, and the NOR gate accordingto an embodiment of the present invention. FIGS. 17A and 17B arecross-sectional views respectively taken along line □-□′ and □-□′ ofFIG. 16A, illustrating structure of the memory cell according to theembodiment of the present invention. FIGS. 18 to 20 are cross-sectionalviews taken along line □-□′ of FIGS. 10B to 16B, FIGS. 10C to 16C, andFIGS. 10D to 16D, illustrating the structure of the memory cellaccording to the embodiment of the present invention.

Referring to FIGS. 10A, 17A and 17B, a first active area 1 b′ and asecond active area 1 a′ are arranged on a semiconductor substrate SUB ina parallel direction to a y axis opposing to each other, and one end ofthe second active area 1 a′ extends to be parallel to an x axis. A thirdactive area 1 b″ and a fourth active area 1 a″ are arranged on asemiconductor substrate SUB in a parallel direction to a y axis opposingto each other, and one end of the fourth active area 1 a″ extends to beparallel to an x axis. A gate pattern 1 c′ is arranged in the x axisdirection to cross over the first and second active areas 1 b′ and 1 a′which are arranged to be parallel to the y axis, and a gate pattern 1 c″is arranged in the x axis direction to cross over the third and fourthactive areas 1 b″ and 1 a″ which are arranged to be parallel to the yaxis. A drain region PD1D is provided on a surface of the first activearea 1 b′ which is located at one side of the gate pattern 1 c′, and asource region PD1S is provided on a surface of the second active area 1a′ which is located on the other side of the gate pattern 1 c′.Likewise, a drain region PD2D is provided on a surface of the thirdactive area 1 b″ which is located at one side of the gate pattern 1 c″,and a source region PD2S is provided on a surface of the fourth activearea 1 a″ which is located on the other side of the gate pattern 1 c″.The gate patterns 1 c′ and 1 c″ may include a gate electrode PD1G of theNMOS transistor PD1 and a capping insulating layer 2 a′ which arestacked in order and a gate electrode PD2G of the NMOS transistor PD2and a capping insulating layer 2 a″ which are stacked in order,respectively, and gate insulating layers 2 b′ and 2 b″ are respectivelyinterposed between the respective gate patterns 1 c′ and 1 c″ and thesemiconductor substrate SUB. A spacer 2 c may be arranged on side wallsof the gate patterns 1 c′ and 1 c″, and an interlayer insulator 2 e isarranged over the whole surface of the semiconductor substrate SUBhaving the NMOS transistors PD1 and PD2. An etching stopper layer 2 dmay be additionally interposed between the interlayer insulator 2 e andthe semiconductor substrate SUB having the NMOS transistors PD1 and PD2.Accordingly, the NMOS transistors PD1 and PD2, which arebulk-transistors, are formed on the semiconductor substrate SUB.

Referring to FIGS. 10B and 18, first and second active areas 20 a′ and20 b′ are arranged on a semiconductor substrate SUB opposing to eachother, and a gate pattern 20 c′ is arranged in the y axis direction tocross over the first and second active areas 20 a′ and 20 b′, and oneend of the gate pattern 20 c′ extends in a direction of the x axis wherethe first active area 20 a′ is located. A drain region N1D of the NMOStransistor N1 is provided on a surface of the first active area 20 a′,and a source region N1S of the NMOS transistor N1 is provided on asurface of the second active area 20 b′. The gate pattern 20 c′ of theNMOS transistor N1 may include a gate electrode N1G of the NMOStransistor N1 and a capping insulating layer 21 a which are stacked inorder, and a gate insulating layer 21 b is interposed between the gatepattern 20 c′ and the semiconductor substrate SUB. A spacer 21 c may bearranged on side walls of the gate pattern 20 c′, and an interlayerinsulator 21 e is arranged over the whole surface of the semiconductorsubstrate SUB having the NMOS transistor N1. An etching stopper layer 21d may be additionally interposed between the interlayer insulator 21 eand the semiconductor substrate SUB having the NMOS transistor N1.Accordingly, the NMOS transistor N1 which is a bulk-transistor whichconstitutes the inverter is formed on the semiconductor substrate SUB.

Referring to FIGS. 10C and 19, first to third active areas 40 a′, 40 b′and 40 a″ are arranged on a semiconductor substrate SUB. A gate pattern40 c′ is arranged in the y axis direction above the first and secondactive areas 40 a′ and 40 b′, and one end of the gate pattern 40 c′ isarranged in a direction of the x axis where the firs active area 40 a′is located. A gate pattern 40 c″ is arranged in the y axis directionabove the second and third active areas 40 b′ and 40 a″, and one end ofthe gate pattern 40 c″ is arranged in a direction of the x axis wherethe third active area 40 a″ is located. One end of the gate pattern 40c′ and one end of the gate pattern 40 c″ are arranged to face each otherin diagonal line direction. The gate pattern 40 c′ of the NMOStransistor N2 may includes a gate electrode N2G of the NMOS transistorN2 and a capping insulating layer 41 a′, and a gate insulating layer 41b′ is interposed between the gate pattern 40 c′ and the semiconductorsubstrate SUB. A drain region N2D of the NMOS transistor N2 is providedon a surface of the first active area 40 a′ of the semiconductorsubstrate SUB, and a source region N2S of the NMOS transistor N2 and adrain region N3D of the NMOS transistor N3 are provided on a surface ofthe second active area 40 b′. A spacer 41 c may be arranged on sidewalls of the gate pattern 40 c′, and an interlayer insulator 41 e isarranged over the whole surface of the semiconductor substrate SUBhaving the NMOS transistor N2. An etching stopper layer 41 d may beadditionally interposed between the interlayer insulator 41 e and thesemiconductor substrate SUB having the NMOS transistor N2. Likewise, thegate pattern 40 c″ of the NMOS transistor N3 is provided in the sameform as the gate pattern 40 c′ of the NMOS transistor N2. Accordingly,the NMOS transistors N2 and N3 which are bulk-transistors, whichconstitute the NAND gate, is formed on the semiconductor substrate SUB.

Referring to FIGS. 10D and 20, an N well N WELL is formed on asemiconductor substrate SUB, and first to third active areas 60 a′, 60b′ and 60 a″ are provided in the N well N WELL. Gate patterns 60 c′ and60 c″ are provided in the same form as those of FIG. 10C. As shown inFIG. 20, the PMOS transistors P4 and P5, which are bulk-transistors, areformed on the semiconductor substrate SUB. The PMOS transistors P4 andP5 have the same form as the NMOS transistors N2 and N3 of FIG. 19.

Referring to FIGS. 11A, 17A and 17B, the drain region PD1D of the NMOStransistor PD1 is electrically connected to a lower node semiconductorplug 3 a′ which penetrates the interlayer insulator 2 e and the etchingstopper layer 2 d, and the drain region PD2D of the NMOS transistor PD2is electrically connected to a lower node semiconductor plug 3 a″ whichpenetrates the interlayer insulator 2 e and the etching stopper layer 2d. Lower body patterns 3 b′ and 3 b″ are arranged on the interlayerinsulator 2 e to respectively cover the lower node semiconductor plugs 3a′ and 3 a″.

Referring to FIGS. 11B and 18, the drain region N1D of the NMOStransistor N1 is electrically connected to a node semiconductor plug 22b, which penetrates the interlayer insulator 21 e and the etchingstopper layer 21 d, and a lower body pattern 22 a is arranged on theinterlayer insulator 21 e to cover the node semiconductor plug 22 b.

Referring to FIGS. 11C and 19, the drain region N2D of the NMOStransistor N2 is electrically connected to a node semiconductor plug 42b, which penetrates the interlayer insulator 41 e and the etchingstopper layer 41 d, and a lower body pattern 42 a is arranged on theinterlayer insulator 41 e to cover the node semiconductor plug 42 b.

In case where the memory cell, the inverter, the NAND gate are arrangedas shown in FIGS. 11A and 11C, the NOR gate of FIG. 11D has the samearrangement as that of FIG. 10D.

Referring to FIGS. 12A, 17A and 17B, a gate pattern 4 b′ of the PMOStransistor PU1 is arranged to cross over the lower body pattern 3 b′,and a gate pattern 4 b″ of the PMOS transistor PU2 is arranged to crossover the lower body pattern 3 b″. An upper node semiconductor plug 4 a′is arranged above the lower body pattern 3 b′ at a location where thelower node semiconductor plug 3 a′ is arranged, and an upper nodesemiconductor plug 4 a″ is arranged above the lower body pattern 3 b″ ata location where the lower node semiconductor plug 3 a″ is arranged.Gate electrodes PU1G and PU2G of the PMOS transistors PU1 and PU2 arerespectively arranged above the lower body patterns 3 b′ and 3 b″. Asource region PU1S and a drain region PU1D of the PMOS transistor PU1are provided in the lower body pattern 3 b′, and a source region PU2Sand a drain region PU2D of the PMOS transistor PU2 are provided in thelower body pattern 3 b″. Accordingly, the PMOS transistors PU1 and PU2,which are thin film transistors, are stacked on the NMOS transistors PD1and PD2.

Referring to FIGS. 12B and 18, a gate pattern 23 a is arranged above thelower body pattern 22 a in the same form as the gate pattern 20 c′. Agate electrode P1G of the PMOS transistor P1 is arranged above the lowerbody pattern 22 a, and a drain region P1D and a source region P1S of thePMOS transistor P1 are provided in the lower body pattern 22 a. Acapping insulating layer 24 a is arranged above the gate electrode P1G,and a gate insulating layer 24 b is arranged below the gate electrodeP1G. A spacer 24 c may be arranged on side walls of the gate pattern 23a, and an interlayer insulator 24 e is arranged over the whole surfaceof the lower body pattern 22 a having the PMOS transistor P1. An etchingstopper layer 24 d may be additionally interposed between the interlayerinsulator 24 e and the lower body pattern 22 a having the PMOStransistor P1. Accordingly, the PMOS transistor P1 is stacked above theNMOS transistor N1.

Referring to FIGS. 12C and 19, gate patterns 43 a′ and 43 a″ arearranged above the lower body pattern 42 a to overlap over the gatepatterns 40 c′ and 40 c″. Gate electrodes P2G and P3G are arranged ofthe PMOS transistors P2 and P3 above the lower body pattern 42 a, and adrain region P2D of the PMOS transistor P2, a source region P2S of thePMOS transistor P2, a source region P3S of the PMOS transistor P3, and adrain region P3D of the PMOS transistor P3 are provided in the lowerbody pattern 42 a. A capping insulating layer 44 a′ is arranged abovethe gate electrode P2G, and a gate insulating layer 44 b′ is arrangedbelow the gate electrode P2G. Likewise, a capping insulating layer 44 a″is arranged above the gate electrode P3G, and a gate insulating layer 44b″ is arranged below the gate electrode P3G. Spacers 44 c′ and 44 c″ arearranged on side walls of the gate patterns 43 a′ and 43 a″, and aninterlayer insulator 44 e is arranged over the whole surface of thelower body pattern 42 a having the PMOS transistors P2 and P3. Anetching stopper layer 44 d may be additionally interposed between theinterlayer insulator 44 e and the lower body pattern 42 a having thePMOS transistors P2 and P3. Accordingly, the PMOS transistors P2 and P3are stacked above the NMOS transistors N2 and N3, respectively.

In case where the memory cell, the inverter, the NAND gate are arrangedas shown in FIGS. 11A and 11C, the NOR gate of FIG. 12D has the samearrangement as that of FIG. 11D.

Referring to FIGS. 13A, 17A and 17B, upper body patterns 6 a′ and 6 a″are arranged on an interlayer insulator 5 e. The upper body patterns 6a′ and 6 a″ are arranged to cover the upper node semiconductor plugs 4a′ and 4 a″, respectively and to overlap over the lower body patterns 3b′ and 3 b″. A word line pattern 6 b is arranged to cross over the upperbody patterns 6 a′ and 6 a″ and to overlap the gate patterns 1 c′ and 1c″. Word lines T1G and T2G are arranged above the upper body patterns 6a′ and 6 a″, and a drain region T1D and a source region T1S of thetransmission transistor T1 are arranged in the upper body pattern 6 a′,and a drain region T2D and a source region T2S of the transmissiontransistor T2 are arranged in the upper body pattern 6 a″. A cappinginsulating layer 7 a is arranged above the word lines T1G and T2G, and agate insulating layer 7 b is arranged below the word lines T1G and T2G,and a pacer 7 c is arranged on a side wall of the word line pattern 6 b.An interlayer insulator 7 e is arranged over the whole surface of theupper body patterns 6 a′ and 6 a″ having the transmission transistors T1and T2. An etching stopper layer 7 d may be additionally interposedbetween the interlayer insulator 7 e and the upper body patterns 6 a′and 6 a″ having the transmission transistors T1 and T2. Accordingly, thetransmission transistors T1 and T2 which are thin film transistors arestacked above the pull-up transistors PU1 and PU2, respectively.

In case where the memory cell is arranged as shown in FIG. 13A, theinverter and the NAND gate of FIGS. 13B and 13C have the samearrangement as that of FIGS. 12B and 12C.

Referring to FIGS. 13D and 20, a drain region P5D of the PMOS transistorP5 is electrically connected to a node semiconductor plug 65 b whichpenetrates interlayer insulators 64 e and 61 e and the etching stopperlayer 41 d, and an upper body pattern 65 a is arranged to cover theinterlayer insulator 64 e and the node semiconductor plug 65 b.

Referring to FIGS. 14A, 17A and 17B, the lower node semiconductor plug 3a′, the upper node semiconductor plug 4 a′, the drain region PD1D of thepull-down transistor PD1, the drain region PU1D of the pull-uptransistor PU1, the source region T1S of the transmission transistor T1,the gate electrode PD2G of the pull-down transistor PD2, and the gateelectrode PU2G of the pull-up transistor PU2 are electrically connectedthrough a node plug 8 a′. The lower node semiconductor plug 3 a″, theupper node semiconductor plug 4 a″, the drain region PD2D of thepull-down transistor PD2, the drain region PU2D of the pull-uptransistor PU2, the source region T2S of the transmission transistor T2,the gate electrode PD1G of the pull-down transistor PD1, and the gateelectrode PU1G of the pull-up transistor PU1 are electrically connectedthrough a node plug 8 a″.

In case where the memory cell is arranged as shown in FIG. 14A, theinverter and the NAND gate of FIGS. 14B and 14C have the samearrangement as that of FIGS. 13B and 13C.

Referring to FIGS. 14D and 20, gate patterns 66 a′ and 66 a″ arearranged above the upper body pattern 65 a to overlap over the gatepatterns 60 c′ and 60 c″. As shown in FIG. 20, gate electrodes N4G andN5G of the NMOS transistors N4 and N5 are arranged above the upper bodypattern 65 a, and a drain region N5D of the NMOS transistor N5, sourceand drain regions N5S and N5D of the NMOS transistors N4 and N5, and asource region N4S of the NMOS transistor N4 are provided in the upperbody pattern 65 a. A capping insulating layer 67 a′ is arranged abovethe gate electrode N5G, and a gate insulating layer 67 b′ is arrangedbelow the gate electrode N5G. Likewise, a capping insulating layer 67 a″is arranged above the gate electrode N4G, and a gate insulating layer 67b″ is arranged below the gate electrode N4G. Spacers 67 c′ and 67 c″ arearranged on side walls of the gate patterns 66 a′ and 66 a″, and aninterlayer insulator 67 e is arranged over the whole surface of theupper body pattern 65 a having the NMOS transistors N4 and N5. Anetching stopper layer 67 d may be additionally interposed between theinterlayer insulator 67 e and the upper body pattern 65 a having theNMOS transistors N4 and N5. Accordingly, the NMOS transistors N4 and N5are stacked above the PMOS transistors P4 and P5, respectively.

Referring to FIGS. 15A, 17A and 17B, an interlayer insulator 9 c isstacked on node plugs 8 a′ and 8 a″ and the interlayer insulator 7 e.The source region PU1S of the pull-up transistor PU1 is electricallyconnected to a power line contact plug 9 a′, and the source region PU2Sof the pull-up transistor PU2 is electrically connected to a power linecontact plug 9 a″. The source region PD1S of the pull-down transistorPD1 is electrically connected to a ground line contact plug 9 b′, andthe source region PD2S of the pull-down transistor PD2 is electricallyconnected to a ground line contact plug 9 b″.

Referring to FIGS. 15B and 18, an interlayer insulator 26 is stacked onthe interlayer insulator 24 e. The node semiconductor plug 22 b, thedrain region N1D of the NMOS transistor N1, the drain region P1D of thePMOS transistor P1 are electrically connected to an output signal linecontact plug 25 a, the source region P1S of the PMOS transistor P1 iselectrically connected to a power line contact plug 25 b, and the sourceregion N1S of the NMOS transistor N1 is electrically connected to aground line contact plug 25 c. Even though not shown, the gateelectrodes P1G and N1G of the PMOS transistor P1 and the NMOS transistorN1 are electrically connected to an input signal line contact plug 25 d.

Referring to FIGS. 15C and 19, an interlayer insulator 46 is stacked onthe interlayer insulator 44 e. The node contact plug 42 b, the drainregion N2D of the NMOS transistor N2, the drain region P2D of the PMOStransistor P2 are electrically connected to an output signal linecontact plug 45 a, the source regions P2S and P3S of the PMOStransistors P2 and P3 are electrically connected to a power line contactplug 45 b, the drain region P3D of the PMOS transistor P3 iselectrically connected to an output signal line contact plug 45 c, andthe source region N3S of the NMOS transistor N3 is electricallyconnected to a ground line contact plug 45 d. The gate electrodes P2Gand N2G of the PMOS transistor P2 and the NMOS transistor N2 areelectrically connected to a first input signal line contact plug 25 e,and the gate electrodes P3G and N3G of the PMOS transistor P3 and theNMOS transistor N3 are electrically connected to a second input signalline contact plug 25 f.

Referring to FIGS. 15D and 20, an interlayer insulator 69 is stacked onthe interlayer insulator 67 e. The node contact plug 65 b, the drainregion P5D of the PMOS transistor P5, the drain region N5D of the NMOStransistor N5 are electrically connected to an output signal linecontact plug 68 a, the source region N5S of the NMOS transistor N5 andthe drain region N4D of the NMOS transistor N4 are electricallyconnected to a ground line contact plug 68 b, the source region N4S ofthe NMOS transistor N4 is electrically connected to an output signalline contact plug 68 c, and the source region P4S of the PMOS transistorP4 is electrically connected to a power line contact plug 68 d. The gateelectrodes P5G and N5G of the PMOS transistor P5 and the NMOS transistorN5 are electrically connected to a first input signal line contact plug68 c, and the gate electrodes P4G and N4G of the PMOS transistor P4 andthe NMOS transistor N4 are electrically connected to a second inputsignal line contact plug 68 d.

Referring to FIGS. 16A, 17A and 17B, an interlayer insulator 11 isarranged on the interlayer insulator 9 c. The power line contact plug 9a′ is covered with a power voltage line 10 b, and the ground linecontact plug 9 b′ is covered with a ground voltage line 10 a. The powerline contact plug 9 a″ is covered with a power voltage line 10 b, andthe ground line contact plug 9 b″ is covered with a ground voltage line10 a. An interlayer insulator 12 is arranged on the interlayer insulator11, and the drain regions T1D and T2D of the transmission transistors T1and T2 are electrically connected to bit line contact plugs 13 a′ and 13a″, respectively. The bit line contact plugs 13 a′ and 13 a″ are coveredwith a bit line 14.

Referring to FIGS. 16B and 18, an interlayer insulator 28 is arranged onthe interlayer insulator 26, the output signal line contact plug 25 a iscovered with an output signal line 27 a, the ground line contact plug 25b is covered with a ground voltage line 27 b, and the power line contactplug 25 c is covered with the power voltage line 27 c. The input signalline contact plug 25 d is covered with an input signal line 27 d.

Referring to FIGS. 16C and 19, an interlayer insulator 48 is arranged onthe interlayer insulator 46, the output signal line contact plug 45 a iscovered with an output signal line 47 a, the power line contact plug 45b is covered with a power voltage line 47 b, the output signal linecontact plug 45 c is covered with an output signal line 47 c, and theground line contact plug 45 d is covered with the ground voltage line 47d. The first input signal line contact plug 45 e is covered with a firstinput signal line 47 e, and the second input signal line contact plug 45f is covered with a second input signal line 47 f.

Referring to FIGS. 16D and 20, an interlayer insulator 71 is arranged onthe interlayer insulator 69, the output signal line contact plug 68 a iscovered with an output signal line 70 a, the ground line contact plug 68b is covered with a ground voltage line 70 b, the output signal linecontact plug 68 c is covered with an output signal line 70 a, and thepower line contact plug 68 d is covered with the power voltage line 70.The first input signal line contact plug 68 e is covered with a firstinput signal line 70 e, and the second input signal line contact plug 68f is covered with a second input signal line 70 f.

The node contact plugs and the upper and lower body patterns may besingle crystal silicon substrates. The upper and lower body patterns maybe poly silicon substrates, and in such instance there is no nodecontact plugs.

In case where the bulk transistors are arranged on the first layer ofthe memory cell and the thin film transistors are arranged on the secondand third layers like the memory cell described above, it is preferredthat the thin film transistors to be arranged on the second and thirdlayers of the peripheral circuit have the same type as the thin filmtransistors arranged on the second and third layers of the memory cellfor the convenience of manufacturing process.

FIGS. 21A and 21B are views illustrating stacking structure of thememory cell array and the peripheral circuit according to a firstembodiment of the present invention. In case where the bulk NMOStransistor, the thin film PMOS transistor, the thin film NMOS transistorare respectively arranged on the first to third layers of the memorycell array as shown in FIG. 21A, it is preferred that the transistorshaving the types of FIG. 21B are arranged on the first to third layersof the peripheral circuit. That is, it is preferred that the bulk NMOStransistor or the bulk PMOS transistor may be arranged on the firstlayer and the thin film PMOS transistor and the thin film NMOStransistor having the same type as the thin film transistors arranged onthe second and third layers of the memory cell are arranged on thesecond and third layers of the peripheral circuit.

FIGS. 22A and 22B are views illustrating stacking structure of thememory cell array and the peripheral circuit according to a secondembodiment of the present invention. In case where the bulk NMOStransistor, the thin film NMOS transistor, the thin film PMOS transistorare respectively arranged on the first to third layers of the memorycell array as shown in FIG. 22A, it is preferred that the transistorshaving the types of FIG. 22B are arranged on the first to third layersof the peripheral circuit. That is, it is preferred that the bulk NMOStransistor or the bulk PMOS transistor may be arranged on the firstlayer and the thin film NMOS transistor and the thin film PMOStransistor having the same type as the thin film transistors arranged onthe second and third layers of the memory cell are arranged on thesecond and third layers of the peripheral circuit.

FIGS. 23A and 23B are views illustrating stacking structure of thememory cell array and the peripheral circuit according to a thirdembodiment of the present invention. In case where the bulk PMOStransistor, the thin film NMOS transistor, the thin film NMOS transistorare respectively arranged on the first to third layers of the memorycell array as shown in FIG. 23A, it is preferred that the transistorshaving the types of FIG. 23B are arranged on the first to third layersof the peripheral circuit. That is, it is preferred that the bulk NMOStransistor or the bulk PMOS transistor is arranged on the first layerand the thin film NMOS transistor and the thin film NMOS transistorhaving the same type as the thin film transistors arranged on the secondand third layers of the memory cell are arranged on the second and thirdlayers of the peripheral circuit.

Of course, the transistors to be arranged on the second and third layersof the peripheral circuit may have the different type from thetransistors to be arranged on the second and third layers of the memorycell array. But, this makes the manufacturing process complicated.

The layout area size of the peripheral circuit as well as the layoutarea size of the memory cell can be reduced.

In the embodiments described above, stacking the transistors whichconstitute the inverter, the NAND gate, and the NOR gate are described.But, it is also possible to stack the transistors which constitutedifferent logic circuits such as an AND gate and an OR gate.

The peripheral circuit of the present invention can be arranged suchthat only transistors which constitute some function blocks such as arow or column decoder other than all function blocks are stacked or onlytransistors which constitute a driver (which is comprised of an inverterin general) at an output terminal of a row and/or column decoder arestacked.

The above described arrangement method of the inverter, the NAND gateand the NOR gate which constitute the peripheral circuit can be usefullyapplied to different semiconductor devices.

If the transistors which form the peripheral circuit as well as thetransistors which form the memory cell array are stacked the waydescribed above, the layout area size of the peripheral circuit can bereduced, and thus the effect of the layout area size of thesemiconductor memory device can be increased.

However, unlike the above described embodiments, the transistors whichform the peripheral circuit may be arranged on a single layer eventhough the transistors of the memory cell array are stacked. In thiscase, it is possible to arrange high performance transistors even thoughit is difficult to reduce the layout area size of a region where theperipheral circuit is arranged.

FIGS. 24A and 24B are views respectively illustrating arrangement oftransistors of a static memory cell and transistors which constitute aninverter of a peripheral circuit of a semiconductor memory deviceaccording to a fourth embodiment of the present invention. The staticmemory cell is arrange the same way as that of FIG. 8A, and the inverteris arranged such that a PMOS transistor P1 and an NMOS transistor N1 arearranged on the same layer like FIG. 5B but are arranged on the thirdlayer 3F other than 1F. Here, the first and second layers serve as dummylayers and do not have any transistors formed thereon.

A method of forming the transistors of the peripheral circuit isexplained below by describing a structure of the inverter of theperipheral circuit of the inventive semiconductor memory device andmanufacturing method thereof.

FIG. 25 is a plan view illustrating the inverter of the peripheralcircuit of FIG. 24B, and FIGS. 26A and 26B to FIGS. 34A and 34B arecross-sectional views illustrating a method for manufacturing the memorycell and the inverter. In FIGS. 26A and 26B to FIGS. 34A and 34B,references “C” and “P” denote a memory cell array region and aperipheral circuit region, respectively. The cross-sectional views ofFIGS. 26A to 34 a are taken along lines I-I′ of FIG. 10A to FIG. 16A andIII-III′ of FIG. 25, and the cross-sectional views of FIGS. 26B to 34Bare taken along lines II-II′ of FIG. 16A and IV-IV′ of FIG. 25.

A semiconductor memory substrate 100 includes a cell region C and aperipheral circuit region P. The structure and arrangement of the cellregion C can be understood easily with the above description, and thus astructure and arrangement of the peripheral circuit region P isexplained below.

Referring to FIG. 25 and FIGS. 26A and 26B, when an interlayer insulator2 e is arranged above the cell region C, the interlayer insulator 2 e isarranged above a portion of the semiconductor substrate SUBcorresponding to the peripheral circuit region P. When an etchingstopper layer 2 d is arranged above the cell region C, the etchingstopper layer 2 d may be arranged above the peripheral circuit region P.The etching stopper layer 2 d preferably has etching selectivity to theinterlayer insulator 2 e. For example, in case where the interlayerinsulator 2 e is formed of a silicon oxide layer, the etching stopperlayer 2 d may be formed of a silicon nitride layer or a siliconoxynitride layer.

Referring to FIG. 25 and FIGS. 27A and 27B, when lower body patterns 3b′ and 3 b″ are arranged above the cell region C, the etching stopperlayer 2 d and the interlayer insulator 2 e arranged above the peripheralcircuit region P are removed, and a peripheral lower body pattern 3 p isarranged to cover the semiconductor substrate SUB above the peripheralcircuit region P. In this case, the etching stopper layer 2 d and theinterlayer insulator 2 e which remain in the cell region C may berespectively regarded as the etching stopper layer pattern and theinterlayer insulator pattern. The peripheral lower body pattern 3 p maybe arranged such that its surface is located on the same imaginaryhorizontal line as surfaces of the lower body patterns 3 b′ and 3 b″above the cell region C. The peripheral lower body pattern 3 p may havea single crystal semiconductor structure. For example, in case where thesemiconductor substrate SUB has a single crystal silicon structure, theperipheral lower body pattern 3 p may have a single crystal siliconstructure.

Referring to FIG. 25 and FIGS. 28A and 28B, when an etching stopper 5 dand an interlayer insulator 5 e which cover first and second loadtransistors TL1 and TL2 are arranged above the cell region C, theetching stopper 5 d and the interlayer insulator 5 e are arranged abovethe peripheral circuit region P. The etching stopper layer 5 dpreferably has etching selectivity to the interlayer insulator 5 e. Forexample, in case where the interlayer insulator 5 e is formed of asilicon oxide layer, the etching stopper layer 5 d may be formed of asilicon nitride layer or a silicon oxynitride layer.

Referring to FIG. 25 and FIGS. 29A and 29B, upper body patterns 6 a′ and6 a″ are arranged above the cell region C, the etching stopper layer 5 dand the interlayer insulator 5 e arranged above the peripheral circuitregion P are removed, and a peripheral upper body pattern 6 p coveringthe peripheral lower body pattern 3 p is arranged above the peripheralcircuit region P. The peripheral upper body pattern 6 p may be arrangedsuch that its surface is located on the same imaginary horizontal lineas surfaces of the upper body patterns 6 b′ and 6 b″ above the cellregion C. The peripheral upper body pattern 6 p may have a singlecrystal semiconductor structure which is the same crystal structure asthe peripheral lower body pattern 3 p. For example, in case where theperipheral lower body pattern 3 p has a single crystal siliconstructure, the peripheral upper body pattern 6 p may have a singlecrystal semiconductor structure such as a single crystal siliconstructure. The peripheral upper and lower body patterns 6 p and 3 p forma peripheral body pattern 6 p′.

The peripheral upper and lower body patterns 6 p and 3 p may have asingle crystal semiconductor structure such as a single crystal siliconstructure formed by a single process. An element isolating insulator 7e′ is arranged on the peripheral upper body pattern 6 p above theperipheral circuit region P.

Referring to FIG. 25 and FIGS. 30A and 30B, when a word line pattern 6 bof NMOS transistors T1 and T2 is arranged above the cell region C, agate pattern 23 a′ of a PMOS transistor P1 which crosses a firstperipheral active area 1 p of the peripheral circuit region P isarranged. The gate pattern 23 a′ of the PMOS transistor P1 may include apoly silicon layer pattern P1G and a PMOS gate metal silicide layer 24a′ which are sequentially stacked. A gate pattern 20 c″ of an NMOStransistor N1 which crosses a second peripheral active area 1 p′ isarranged. The gate pattern 20 c″ of the NMOS transistor N1 may include apoly silicon layer pattern N1G and an NMOS gate metal silicide layer 21a′ which are sequentially stacked. The gate metal silicide layers 21 a′and 24 a′ may be formed of a nickel silicide layer, a cobalt silicidelayer, a titanium silicide layer or a tungsten silicide layer. The NMOStransistors T1 and T2 above the cell region C may also include a metalsilicide layer 7 d′. On surfaces of the first peripheral active area 1 plocated on both sides of the PMOS gate pattern 23 a′, a drain region P1Dand a source region P1S of the PMOS transistor P1 are arranged. The PMOSgate pattern 23 a′ forms the PMOS transistor P1 together with the sourceand drain regions P1S and P1D. Similarly, on surfaces of the secondperipheral active area 1 p′ located on both sides of the NMOS gatepattern 20 c″, a drain region N1D and a source region N1S of the NMOStransistor NP1 are arranged. The NMOS gate pattern 20 c″ forms the NMOStransistor N1 together with the source and drain regions N1S and N1D. Onsurfaces of the source and drain regions P1S and P1D of the PMOStransistor P1 and surfaces of the source and drain regions N1S and N1Dof the NMOS transistor N1, metal silicide layers 7 d′ are respectivelyarranged. The metal silicide layers 7 d′ may be formed of a nickelsilicide layer, a cobalt silicide layer, a titanium silicide layer or atungsten silicide layer. An interlayer insulator 7 e is arranged on thewhole surface of the semiconductor substrate having the NMOS transistorN1 and the PMOS transistor P1. In addition, an etching stopper layer 7 dmay be interposed between the semiconductor substrate SUB and theinterlayer insulator 7 e. The etching stopper layer 7 d preferably hasetching selectivity to the interlayer insulator 7 e. For example, incase where the interlayer insulator 7 e is formed of a silicon oxidelayer, the etching stopper layer 7 d may be formed of a silicon nitridelayer or a silicon oxynitride layer.

Referring to FIG. 25 and FIGS. 31A and 31B, an interlayer insulator 9 cis arranged on the interlayer insulator 7 e above the peripheral circuitregion P like the cell region C.

Referring to FIG. 25 and FIGS. 32A and 32B, a peripheral power linecontact plug 9 e, a peripheral ground line contact plug 9 f′, and outputsignal line contact plugs 9 f and 9 e′ may be arranged in the interlayerinsulator 9 c above the peripheral circuit region P.

An interlayer insulator 11 which covers the peripheral power linecontact plug 9 e, the peripheral ground line contact plug 9 f′, and theoutput signal line contact plugs 9 f and 9 e′ is arranged.

Referring to FIG. 25 and FIGS. 33A and 33B, in the interlayer insulator11 above the peripheral circuit region P, a peripheral power line 10 eis arranged to cover the peripheral power line contact plug 9 e, aperipheral ground line 10 f is arranged to cover the peripheral groundline contact plug 9 f′, and an output signal line 10 g is arranged tocover the output signal line contact plugs 9 f and 9 e′.

An interlayer insulator 12 is arranged to cover the peripheral powerline 10 e, the peripheral ground line 10 f, and the output signal line10 g.

In the above described way, the transistors P1 and N1 which form theinverter are arranged on the third layer of the peripheral circuitregion P. Of course, transistors which form an NAND gate and a NOR gatemay be also arranged on the third layer of the peripheral circuit regionP.

A method for manufacturing an SRAM according to the present invention isexplained below with reference to FIG. 16, FIG. 25, and FIGS. 26A and26B to FIGS. 34A and 34B.

Referring to FIG. 16A, FIG. 25, and FIGS. 26A and 26B, a semiconductorsubstrate SUB having a cell region C and a peripheral circuit region Pis prepared. The semiconductor substrate SUB may be a single crystalsilicon substrate. The semiconductor substrate SUB may be a p-typesilicon substrate. An element isolating layer 1′ is formed on apredetermined region of the semiconductor substrate SUB to define firstand second cell active areas 1 b′ and 1 b″. The element isolating layer1′ is preferably formed in the cell region C. The first and secondactive areas 1 b′ and 1 b″ are formed parallel to a y axis. In addition,the element isolating layer 1′ is formed to provide a first groundactive area 1 a′ which extends along an x axis from one end of the firstactive area 1 b′ and a fourth active area 1 a″ which extends along an xaxis from one end of the second active area 1 b″. The second and fourthactive areas 1 a′ and 1 a″ are formed to face each other.

Gate insulating layers 2 b′ and 2 b″ are formed on the first to fourthactive areas 1 a′, 1 b′, 1 a″, and 1 b″. A gate conductive layer and acapping insulating layer are sequentially formed on the whole surface ofthe semiconductor substrate SUB having the gate insulating layers 2 b′and 2 b″. The gate conductive layer may be formed of a silicon layer,and the capping insulating layer may be formed of a silicon oxide layeror a silicon nitride layer. The gate capping insulating layer and thegate conductive layer are patterned to form a gate pattern 1 c′ whichcrosses the first active area 1 b′ and a gate pattern 1 c″ which crossesthe third active area 1 b″. As a result, the gate pattern 1 c′ is formedto have a gate electrode PD1G and a capping insulating layer 2 a′ whichare sequentially stacked, and a gate pattern 1 c″ is formed to have agate electrode PD2G and a capping insulating layer 2 a″ which aresequentially stacked. A process for forming the capping insulating layermay be omitted. In this case, the gate pattern 1 c′ has only the gateelectrode, and the gate pattern 1 c″ has only the gate electrode.

Impurity ions are doped into the first to fourth active areas 1 a′, 1b′, 1 b″, and 1 a″ by using the gate patterns 1 c′ and 1 c″ as an iondoping mask. As a result, a source region PD1S and a drain region PD1Dwhich are separated from each other are formed in the first active area1 b′, and a source region PD2S and a drain region PD2D which areseparated from each other are formed in the third active area 1 b″. Thesource regions PD1S and PD2S and the drain regions PD1D and PD2D may ben-type ion-doped regions. The source region PD1S and the drain regionPD1D are formed on both sides of a channel area below the driving gatepattern 1 c′, and the source region PD2S and the drain region PD2D areformed on both sides of a channel area below the driving gate pattern 1c″. The source region PD2S is also formed in the second active area 1a′, and the source region PD2S is also formed in the fourth active area1 a″. The source regions PD1S and PD2S and the drain regions PD1D andPD2D may be formed to have a lightly doped drain (LDD) type structure.Gate spacers 2 c are formed on sidewalls of the gate patterns 1 c′ and 1c″. The gate spacers 2 c may be formed of a silicon nitride layer or asilicon oxide layer.

The first driving gate pattern 1 c′, the source region PD1S and thedrain region PD1D form the first bulk transistor, i.e., the first NMOStransistor PD1, and the second driving gate pattern 1 c″, the sourceregion PD2S and the drain region PD2D form the second bulk transistor,i.e., the second NMOS transistor PD2.

An etching stopper layer 2 d and an interlayer insulator 2 e aresequentially formed on the whole surface of the semiconductor substrateSUB having the first and second transistors PD1 and PD2. The interlayerinsulator 2 e is preferably planarized by using a chemical mechanicalpolishing technique. In this case, the etching stopper layer 2 d on thegate patterns 1 c′ and 1 c″ may serve as a chemical mechanical polishingstopper.

Referring to FIG. 16A, FIG. 25 and FIGS. 27A and 27B, the interlayerinsulator 2 e and the etching stopper layer 2 d are patterned to exposepredetermined regions of the drain regions PD1D and PD2D of the cellregion C and expose the semiconductor substrate of the peripheralcircuit region P. As a result, the lower node contact holes 2 f′ and 2f″ which sequentially penetrate the interlayer insulator layer 2 e andthe etching stopper layer 2 d to expose the predetermined regions of thedrain regions PD1D and PD2D of the cell region C may be formed in thecell region C. In this case, the interlayer insulator layer 2 e and theetching stopper layer 2 d may be respectively regarded as the interlayerinsulator layer pattern and the etching stopper layer pattern. Asemiconductor layer 3 p is formed to cover the interlayer insulator 2 eand the semiconductor substrate SUB of the peripheral circuit region Pwhile filling the lower node contact holes 2 f′ and 2 f″. Thesemiconductor layer 3 p may be formed of a single crystal semiconductorstructure. The single crystal semiconductor structure may be formed byan epitaxial technique. In more detail, a single crystal semiconductorstructure, i.e., an epitaxial layer which covers the interlayerinsulator 2 e and the semiconductor substrate SUB above the peripheralcircuit region P while filling the lower node contact holes 2 f′ and 2f″ is formed. The epitaxial technique may be a selective epitaxialgrowth technique. The epitaxial layer may be formed by a selectiveepitaxial growth technique which uses as a seed layer a predeterminedregion of the semiconductor substrate SUB exposed by the lower nodecontact holes 2 f′ and 2 f″ and the semiconductor substrate SUB of theperipheral circuit region P. In case where the semiconductor substrateSUB is a single crystal silicon substrate, the epitaxial layer may beformed to have a single crystal silicon structure. That is, theepitaxial layer may be formed of a single crystal semiconductorstructure. Then, an upper surface of the epitaxial layer may beplanarized by using a planarization technique such as a chemicalmechanical polishing (CMP) technique.

Meanwhile, a semiconductor layer which fills the lower node contactholes 2 f′ and 2 f″ and covers the interlayer insulator 2 e and thesemiconductor substrate SUB of the peripheral circuit region P may beformed of a non-single crystal semiconductor layer. For example, thesemiconductor layer may be formed of an amorphous silicon layer or apoly silicon layer. The semiconductor layer may be planarized. In thiscase, before or after planarizing the semiconductor layer, thesemiconductor layer may be crystallized using an epitaxial technique,i.e., solid phase epitaxial technique which employs as a seed layer thesemiconductor substrate which contacts the semiconductor layer. As aresult, the semiconductor layer can be formed as a single crystalsemiconductor structure.

The single crystal semiconductor structure is patterned to form lowerbody patterns 3 b′ and 3 b″ above the cell region while forming aperipheral lower body pattern 3 p which covers the semiconductorsubstrate SUB of the peripheral circuit region P. The lower bodypatterns 3 b′ and 3 b″ are preferably formed to overlap the first andthird active areas 1 b′ and 1 b″, respectively. The lower body patterns3 b′ and 3 b″ are formed to cover the lower node contact holes 2 f′ and2 f″, respectively.

Preferably, the lower body pattern 3 b′ has an extension portion whichoverlaps a portion of the second active area 1 a′. Similarly, it ispreferred that the cell lower body pattern 3 b″ has an extension portionwhich overlaps a portion of the fourth active area 1 a″.

Meanwhile, a single crystal semiconductor layer is formed to fill thelower node contact holes 2 f′ and 2 f″ and cover the interlayerinsulator 2 e and the semiconductor substrate SUB of the peripheralcircuit region P. The single crystal semiconductor is subjected to thechemical mechanical polishing process to form the lower node contactplugs 3 a′ and 3 a″ in the lower node contact holes 2 f′ and 2 f″ andform a peripheral single crystal semiconductor layer which covers thesemiconductor substrate SUB of the peripheral circuit region P. Thesingle crystal semiconductor layer may be formed by an epitaxialtechnology. Subsequently, a semiconductor layer, i.e., a lower bodylayer is formed on the whole surface of the semiconductor substrate SUBhaving the lower node contact plugs 3 a′ and 3 a″. In case where thelower node semiconductor plugs 3 a′ and 3 a″ are single crystal siliconplugs, the lower body layer may be formed of a non-single crystalsemiconductor layer, i.e., an amorphous silicon layer or a polysiliconlayer. The lower body layer may be crystallized using a solid phaseepitaxial (SPE) technique which is well known to a person havingordinary skill in the art. For example, the solid phase epitaxialtechnique may include a process for heat-treating and crystallizing thelower body patterns 3 b′ and 3 b″ at a temperature of about 500° C. toabout 800° C.

Meanwhile, the single crystal semiconductor structure is patterned toform the lower body patterns 3 b′ and 3 b″ while removing the singlecrystal semiconductor structure of the peripheral circuit region P toexpose the semiconductor substrate SUB of the peripheral circuit regionP.

Referring to FIG. 16A, FIG. 25, and FIGS. 28A and 28B, a gate insulatinglayer is formed on surfaces of the lower body patterns 3 b′ and 3 b″.Load gate patterns 4 b′ and 4 b″ are formed to cross over the lower bodypatterns 3 b′ and 3 b″. The gate patterns 4 b′ and 4 b″ are preferablyformed to overlap the gate patterns 1 c′ and 1 c″, respectively. Thegate patterns 4 b′ and 4 b″ may be formed the same way as the drivinggate patterns 1 c′ and 1 c″. Thus, the gate pattern 4 b′ may be formedto have a gate electrode PU1G and a capping insulating layer 5 a′ whichare sequentially stacked, and the gate pattern 4 b″ may be formed tohave a gate electrode PU2G and a capping insulating layer 5 a which aresequentially stacked.

Impurity ions are doped into the lower body patterns 3 b′ and 3 b″ usingthe gate patterns 4 b′ and 4 b″ as an ion doping make. As a result,source and drain regions PU1S and PU1D which are separated from eachother are formed in the lower body pattern 3 b′, and source and drainregions PU2S and PU2D which are separated from each other are formed inthe lower body pattern 3 b″. The source and drain regions PU1S and PU1Dare formed on both sides of a channel area below the gate pattern 4 b′,and the source and drain regions PU2S and PU2D are formed on both sidesof a channel area below the gate pattern 4 b″. The source regions PU1Sand PU2S are formed in the extension portion of the lower body pattern 3b′ and in the extension portion of the lower body pattern 3 b″,respectively. The source region PU1S is formed in the lower body pattern3 b′ above the lower node contact plug 3 a′, and the drain region PU2Dis formed in the lower body pattern 3 b″ above the lower nodesemiconductor plug 3 a″. Here, the drain region PU1D may contact thelower node semiconductor plug 3 a′, and the drain region PU2D maycontact the lower node semiconductor plug 3 a″.

The source regions PU1S and PU2S and the drain regions PU1D and PU2D maybe p-type ion-doped regions.

The source region PU1S and PU2S and the drain regions PU1D and PU2D maybe formed to have an LDD-type structure.

Spacers 5 c may be formed on sidewalls of the load gate patterns 4 b′and 4 b″. The spacers 5 c may be formed of a silicon nitride layer or asilicon oxide layer.

The gate pattern 4 b′, the source region PU1S and the drain region PU1Dform a lower thin film transistor, i.e., a PMOS transistor PU1, and thegate pattern 4 b″, the source region PU2S and the drain region PU2D forma lower thin film transistor, i.e., a PMOS transistor PU2. The PMOStransistors PU1 and PU2 may be load transistors. An interlayer insulator5 e is formed on the whole surface of the semiconductor substrate havingthe load transistors PU1 and PU2. Before forming the interlayerinsulator 5 e, an etching stopper layer 5 d may be additionally formed.The etching stopper layer 5 d and the interlayer insulator 5 e may beformed the same method as the etching stopper layer 3 d and theinterlayer insulator 3 e. In this case, the interlayer insulator 5 e andthe etching stopper layer 5 d may be respectively regarded as theinterlayer insulator pattern and the etching stopper layer pattern.

Referring to FIG. 16A, FIG. 25, and FIGS. 29A and 29B, the etchingstopper layer 5 d and the interlayer insulator 5 e are patterned toexpose the source and drain regions PU1S and PU2D and expose theperipheral lower body pattern 3 p of the peripheral circuit region P. Asa result, the upper node contact holes 4 f′, and 4 f″ which sequentiallypenetrate the interlayer insulator 5 e and the etching stopper layer 5 dto expose the source and drain regions PU1S and PU2D may be formed inthe cell region C. A semiconductor layer is formed to fill the uppernode contact holes 4 f′ and 4 f″ on the interlayer insulator 5 e and theperipheral circuit region P. The semiconductor layer may be formed of asingle crystal semiconductor structure. The single crystal semiconductorstructure may be formed by an epitaxial technique. The epitaxialtechnique may be a selective epitaxial technique. In more detail, asingle crystal semiconductor structure, i.e., an epitaxial layer whichcovers the interlayer insulator 5 e and the peripheral lower bodypattern 3 p and fills the upper node contact holes 4 f′ and 4 f″ isformed. The epitaxial layer may be formed to have a single crystalsilicon structure. The epitaxial layer may be formed by a selectiveepitaxial growth technique which uses as a seed layer a predeterminedregion of the cell lower body patterns 3 b′ and 3 b″ exposed by theupper node contact holes 4 f′ and 4 f″ and the peripheral body pattern 3p.

As described in FIGS. 27A and 27B, in case where the single crystalsemiconductor structure is patterned to form the cell lower bodypatterns 3 b′ and 3 b″ while removing the single crystal semiconductorstructure of the peripheral circuit region P to expose the semiconductorsubstrate SUB of the peripheral circuit region P, the single crystalsemiconductor structure, i.e., the epitaxial layer may be formed by aselective epitaxial growth technique which uses as a seed layerpredetermined regions of the cell lower body patterns 3 b′ and 3 b″exposed by the upper node contact holes 4 f′ and 4 f″ and thesemiconductor substrate SUB of the peripheral circuit region P. Then, anupper surface of the epitaxial layer may be planarized by using aplanarization technique such as a chemical mechanical polishing (CMP)technique.

Meanwhile, a semiconductor layer which fills the upper node contactholes 4 f′ and 4 f″ may be formed of a non-single crystal semiconductorlayer on the interlayer insulator 5 e and the peripheral circuit regionP. For example, the semiconductor layer may be formed of an amorphoussilicon layer or a poly silicon layer. The semiconductor layer may beplanarized. In this case, before or after planarizing the semiconductorlayer, the semiconductor layer may be crystallized using an epitaxialtechnique, i.e., solid phase epitaxial technique which employs as a seedlayer the single crystal semiconductor structures which are arrangedbelow the semiconductor layer and contact the semiconductor layer. As aresult, the semiconductor layer can be formed as a single crystalsemiconductor structure.

The single semiconductor structure is patterned to form upper bodypatterns 6 a′ and 6 a″ above the cell region C and form a peripheralupper body pattern 6 p above the peripheral circuit region P. Here, theperipheral upper body pattern 6 p is formed to have a peripheral trench6 b which defines first and second peripheral active areas 1 p and 1 p′.As a result, the peripheral upper body pattern 6 p having the peripheraltrench 6 b is formed on the peripheral lower body pattern 3 p of theperipheral circuit region P. The peripheral lower and upper bodypatterns 3 p and 6 p have the substantially same single crystalstructure and may form a peripheral body pattern 6 p′.

Meanwhile, in case of performing a process for patterning the previouslyformed single crystal semiconductor structure to expose thesemiconductor substrate SUB of the peripheral circuit region P, thesequentially formed single crystal semiconductor structure may be formedto directly contact the semiconductor substrate SUB of the peripheralcircuit region P. As a result, the peripheral body pattern 6 p′ may beformed of a single crystal semiconductor structure formed by a singleprocess, i.e., a single crystal silicon structure. The upper bodypatterns 6 a′ and 6 a″ are formed to cover the upper node contact holes4 f′ and 4 f″, respectively. The epitaxial layers formed in the uppernode contact holes 4 f′ and 4 f″ may be defined as the upper nodesemiconductor plugs 4 a′ and 4 a″. The upper body patterns 6 a′ and 6 a″are preferably formed to respectively overlap the lower body patterns 3b′ and 3 b″. However, it is preferred that the upper body patterns 6 a′and 6 a″ do not overlap the extension portions of the lower bodypatterns 3 b′ and 3 b″.

Meanwhile, a single crystal semiconductor layer which fills the uppernode contact holes 4 f′ and 4 f″ may be formed on the interlayerinsulator 5 e and the semiconductor substrate SUB of the peripheralcircuit region P. Subsequently, the single crystal semiconductor layeris planarized to form the first and second upper node contact plugs 4 a′and 4 a″ and form a single crystal semiconductor layer which remainsabove the peripheral circuit region P. The single crystal semiconductorlayer may be a single crystal silicon structure formed by the epitaxialtechnique. Then, a semiconductor layer, i.e., an upper body layer may beformed on the whole surface of the semiconductor substrate SUB havingthe upper node semiconductor plugs 4 a′ and 4 a″. In case where theupper node semiconductor plugs 4 a′ and 4 a″ are single crystal siliconplugs, the upper body layer may be formed of an amorphous silicon layeror a poly silicon layer. The upper body layer is patterned to form thefirst and second body patterns 6 a′ and 6 a″, and the upper body layerabove the peripheral circuit region P is patterned to form a peripheraltrench 6 b which defines the first and second peripheral active areas 1p and 1 p′. The first and second upper body patterns 6 a′ and 6 a″ maybe crystallized by a solid phase epitaxial technique which is well knownto a person having ordinary skill in the art. The element isolatinginsulating layer 7 e′ may be formed in the peripheral trench 6 b. Here,when the element isolating insulating layer 7 e′ may be formed in theperipheral trench 6 b, the element isolating insulating layer 7 e′ whichfills a space between the upper body patterns 6 a′ and 6 a″ above thecell region C may be formed.

Meanwhile, the process for forming the element isolating insulatinglayer in the peripheral trench 6 b may be omitted.

Referring to FIG. 16A, FIG. 25, and FIGS. 30A and 30B, a gate insulatinglayer is formed on the cell upper body patterns 6 a′ and 6 a″ and theperipheral body pattern 6 p. A transmission gate pattern 6 b, i.e., aword line insulated to cross over the upper body patterns 6 a′ and 6 a″is formed, and a peripheral PMOS gate pattern 23 a′ and a peripheralNMOS gate pattern 20 c″ which are insulated to cross over the first andsecond peripheral active areas 1 p and 1 p′ of the peripheral bodypattern P are formed.

Meanwhile, before forming the peripheral gate patterns 23 a′ and 20 c″,impurity ions may be doped into the first and second peripheral activeareas 1 p and 1 p′ to form an n-type well 7 f and a p-type well 7 f′. Incase where the peripheral body pattern 6 p′ is formed to have an n-typeor p-type conductivity, a separate ion doping process for forming then-type or p-type well may be omitted.

Impurity ions are doped into the upper body patterns 6 a′ and 6 a″ usingthe word line 6 p as an ion doping mask. Further, impurity ions aredoped into the first and second peripheral active areas 1 p and 1 p′using the peripheral gate patterns 23 a′ and 20 c″ of the peripheralcircuit region P and the element isolating insulating layer 7 e as anion doping mask. As a result, source and drain regions T1S and T1D whichare separated from each other are formed in the upper body pattern 6 a′,source and drain regions T2S and T2D which are separated from each otherare formed in the upper body pattern 6 a″, source and drain regions P1Sand P1D which are separated from each other are formed in the peripheralactive area 1 p, and source and drain regions N1S and N1D which areseparated from each other are formed in the peripheral active area 1 p′.In case where the source and drain regions T1S and T1D, T2S and T2D, P1Sand P1D, and N1S and N1D have an LDD-type structure, an insulatingspacer 7 c may be formed on sidewalls of the word line 6 b and sidewallsof the peripheral gate patterns 23 a′ and 20 c″.

The source regions T1S and T2S and the drain regions T1D and T2D of thecell region C may be n-type ion-doped regions. The source and drainregions P1S and P1D of the peripheral active area 1 p may be p-typeion-doped regions, and the source and drain regions N1S and N1D of theperipheral active area 1 p′ may be n-type ion-doped regions. The wordline 6 b and the source and drain regions T1S and T1D constitute a cellupper thin film transistor, i.e., an NMOS transmission transistor T1,and the word line 6 b and the source and drain regions T2S and T2Dconstitute a cell upper thin film transistor, i.e., an NMOS transmissiontransistor T2. The peripheral PMOS gate pattern 23 a″ and the source anddrain regions P1S and P1D constitute a peripheral PMOS transistor P1,and the peripheral NMOS gate pattern 20 c″ and the source and drainregions N1S and N1D constitute a peripheral NMOS transistor N1.

A metal silicide layer may be selectively formed on surfaces of the gateelectrodes and/or the source and drain regions of the peripheraltransistors P1 and N1. For example, a silicide process for loweringelectrical resistance of the gate electrodes and the source and drainregions of the NMOS transmission transistor T1, the NMOS transmissiontransistor T2, the peripheral PMOS transistor P1, the peripheral NMOStransmission transistor N1. The silicide process is a process technologyfor selectively forming the metal silicide layer on the gate electrodeand the source and drain regions to lower the electrical resistance ofthe gate electrode and the source and drain regions. The silicideprocess includes a silicidation annealing process. As the silicidationannealing process, either a rapid thermal process which employs aradiation method using a light source such as a lamp or a conductionmethod using a hot plate or an annealing process of a convection methodusing a heat transfer gas.

In more detail, after forming the gate insulting layer on the cell upperbody patterns 6 a′ and 6 a″ and the peripheral body pattern 6 p, asilicon layer such as a poly silicon layer is formed on the substratehaving the gate insulating layer. The poly silicon layer is patterned toform a poly silicon layer pattern which crosses over the cell upper bodypatterns 6 a′ and 6 a″ and form poly silicon layer patterns P1G and N1Gwhich cross over the peripheral active areas 1 p and 1 p′ of theperipheral body pattern 6 p. An insulating spacer 7 c is formed onsidewalls of the poly silicon layer patterns T1G, T2G, P1G, and N1G. Theinsulating spacer 7 c may include a silicon oxide layer or a siliconnitride layer. Subsequently, the source and drain regions T1S and T1D,T2S and T2D, P1S and P1D, and N1S and N1D are formed. The poly siliconlayer patterns T1G, T2G, P1G, and N1G and the source and drain regionsT1S and T1D, T2S and T2D, P1S and P1D, and N1S and N1D may be exposed.Subsequently, a metal layer is formed on the semiconductor substratehaving the poly silicon layer patterns T1G, T2G, P1G, and N1G and thesource and drain regions T1S and T1D, T2S and T2D, P1S and P1D, and N1Sand N1D. The metal layer may be formed of a nickel layer, a tungstenlayer, a titanium layer, or a cobalt layer. Then, the metal layer may besubjected to the silicidation annealing process.

On the other hand, after forming the gate insulating layer on the cellupper body patterns 6 a′ and 6 a″ and the peripheral body pattern 6 p, agate conductive layer containing a metal silicide layer, for example, apoly silicon layer and a metal silicide layer which are sequentiallystacked may be formed on the semiconductor substrate having the gateinsulating layer. Next, a hard mask insulating layer may be formed onthe gate conductive layer. The hard mask insulating layer and the gateconductive layer may be patterned to form a poly silicon layer pattern,a metal silicide layer pattern and a hard mask pattern which aresequentially stacked. As a result, the poly silicon layer pattern, themetal silicide layer pattern and the hard mask pattern which aresequentially stacked may be formed as a gate pattern, and the source anddrain regions may be exposed. A metal layer may be formed on thesemiconductor substrate having the gate pattern and then may besubjected to the silicidation annealing process. As a result, metalsilicide layers may be formed in the source an drain region.

Using the silicide process, a gate metal silicide layer 7 a, a PMOS gatemetal silicide layer 24 a′ and the NMOS gate metal silicide layer 21 a′may be respectively formed on the word line 6 p, the peripheral PMOSgate pattern 23 a′ and the peripheral NMOS gate pattern 20 c″, the metalsilicide layers may be formed on respective surfaces of the source anddrain regions T1S and T1D and T2S and T2D of the word line 6 b, themetal silicide layers 7 d′ may be formed on respective surfaces of thesource and drain regions P1S and P1D of the peripheral PMOS gate pattern24 a′, the metal silicide layers 7 d′ may be formed on the respectivesurfaces of the source and drain regions N1S and N1D of the peripheralNMOS gate pattern 20 c″. As a result, the word line 6 p may be formed tohave the poly silicon layer patterns T1G and T2G and the gate metalsilicide layer 7 a which are sequentially stacked. The peripheral PMOSgate pattern 23 a′ may be formed to have the poly silicon layer patternP1G and the PMOS gate metal silicide layer 24 a′ which are sequentiallystacked. The peripheral NMOS gate pattern 20 c″ may be formed to havethe poly silicon layer pattern N1G and the NMOS gate metal silicidelayer 24 a′ which are sequentially stacked. Accordingly, it is possibleto lower the electrical resistance of the gate electrode and the sourceand drain regions of the peripheral transistors P1 and N1. That is,transmission rate of the electrical signal applied to the gateelectrodes of the peripheral transistors P1 and N1 can be improved.Further, since the sheet resistance of the source and drain regions ofthe peripheral transistors P1 and N1 can be improved, drivability of theperipheral transistors P1 and N1 can be improved. As a result, it ispossible to implement the high performance MOS transistors in theperipheral circuit region P. Furthermore, since the electricalcharacteristics of the gate electrode and the source and drain regionsof the transmission transistors T1 and T2 of the cell region C can beimproved, performance of the transmission transistors T1 and T2 can beimproved.

Thus, since the silicide process for improving the performance of thetransistors of the peripheral circuit region P can be performed,performance of the SRAM can be improved. Further, in the semiconductorintegrated circuits which employ the thin film transistors, the highperformance MOS transistors having improved electrical characteristicscan be obtained since the MOS transistors of the peripheral circuitregion are formed after the peripheral body pattern is formed, asdescribed above. The performance of the SRAM depends on the peripheralcircuits formed in the peripheral circuit region, and thus theperformance of the SRAM is determined by the performance of thetransistors which are necessary components of the peripheral circuits.In the embodiments of the present invention, since the peripheral bodypattern 6 p is formed by using the semiconductor substrate of theperipheral circuit region as the seed layer, the peripheral body pattern6 p may be closer in crystallinity to the semiconductor substrate. Thatis, since the epitaxial layer is formed from the whole surface of thesemiconductor substrate of the peripheral circuit region, the singlecrystal structure of the peripheral body pattern may be closer to thesingle crystal structure of the semiconductor substrate. The peripheraltransistors formed in the peripheral circuit region P may have similarcharacteristics to the bulk transistors substantially formed on thesemiconductor substrate. Further, the peripheral transistors formed inthe peripheral circuit region P are not affected by heat which may begenerated during a process for forming the thin film transistors of thecell region C. That is, the epitaxial process and the spacer process formanufacture the thin film transistors of the cell region C can beperformed at a typical high temperature. Characteristics of thetransistors exposed to the processes performed at the high temperaturemay be degraded, but the transistors of the peripheral circuit region Pare not affected by the high temperature processes. Furthermore, sincethe metal silicide layers can be respectively formed on the gateelectrode and the source and drain regions of the transistors of theperipheral circuit region P, the performance of the transistors of theperipheral circuit region P can be more improved. Thus, reliability ofthe semiconductor device can be more improved.

The interlayer insulator 7 e is formed on the whole surface of thesemiconductor substrate having the NMOS transistors T1 and T2, the PMOStransistor P1, and the NMOS transistor N1. The etching stopper layer 7 dmay be additionally formed before forming the interlayer insulatinglayer 7 e.

Referring to FIG. 16A, FIG. 25, and FIGS. 31A and 31B, the interlayerinsulators 2 e, 5 e and 7 e and the etching stopper layers 2 d, 5 d and7 d are etched to form a node contact hole 7 f′ which exposes the sourceregion T1S of the NMOS transistor T1, the upper node semiconductor plug4 a′, the drain region PU1D of the transistor PU1, the lower nodesemiconductor plug 3 a′, the gate electrode PU2G, and the gate electrodePD2G and to form a node contact hole 7 f″ which exposes the sourceregion T2S of the NMOS transistor T2, the upper node semiconductor plug4 a″, the drain region PU2D of the transistor PU2, the lower nodesemiconductor plug 3 a′″ the gate electrode PUIG, and the gate electrodePD1G.

Meanwhile, in case where the lower node semiconductor plugs 3 a′ and 3a″ have the different conductive type from the drain regions PD1D andPD2D or are intrinsic semiconductors, the node contact holes 7 f′ and 7f″ may be formed to expose the drain regions PD1D and PD2D of the MOStransistors PD1 and PD2, respectively.

A conductive layer is formed on the semiconductor substrate having thenode contact holes 7 f′ and 7 f″. The conductive layer is planarized toexpose the interlayer insulator 7 e. As a result, the node contact plugs8 a′ and 8 a″ are formed. The node contact plugs 8 a′ and 8 a″ arepreferably formed of a conductive layer which shows ohmic contactcharacteristics to both p- and n-type semiconductors. For example, theconductive layer may be formed of a metal layer such as a tungstenlayer. Further, the conductive layer may be formed by sequentiallystacking a barrier metal layer such as a titanium nitride layer and ametal layer such as a tungsten layer. In this case, each of the nodecontact plugs 8 a′ and 8 a″ may be formed to have a tungsten plug and abarrier metal layer pattern which surrounds the tungsten plug.

The interlayer insulator 9 c is formed on the semiconductor substratehaving the node contact plugs 8 a′ and 8 a″.

Referring to FIG. 16A, FIG. 25, and FIGS. 32A and 32B, the ground linecontact plugs 9 b′ and 9 b″ which penetrate the interlayer insulators 2e, 5 e, 7 e, and 9 c and the etching stoppers 2 d, 5 d and 7 d torespectively contact the source region PD1S in the second active area 1a′ and the source region PD2S of the fourth active area 1 a″ are formed.While forming the ground line contact plugs 9 b′ and 9 b″, the powerline contact plugs 9 a′ and 9 a″ are formed which respectively contactthe extension portion of the lower body pattern 3 b′ (source region PU1Sof the load transistor) and the extension portion of the lower bodypattern 3 b″ (source region PU2S of the load transistor). Further, whileforming the ground line contact plugs 9 b′ and 9 b″, the output signalline contact plug 9 e and the peripheral power line contact plug 9 fwhich respectively contact the source and drain regions P1S and P1D ofthe PMOS transistor P1, and the output signal line contact plug 9 e′ andthe peripheral power line contact plug 9 f′ which respectively contactthe source and drain regions N1S and N1D of the NMOS transistor N1. Thecontact plugs 9 a′, 9 a″, 9 b′, 9 b″, 9 f, 9 e, 9 f′, and 9 e′ arepreferably formed of a conductive layer which shows the ohmic contactcharacteristics to both p- and n-type semiconductors. For example, thecontact plugs 9 a′, 9 a″, 9 b′, 9 b″, 9 f, 9 e, 9 f′, and 9 e′ may beformed the same way as the method of forming the node contact plugs 8 a′and 8 a″ which is described with reference to FIGS. 31A and 31B.

The interlayer insulator 11 is formed on the semiconductor substratehaving the contact plugs 9 a′, 9 a″, 9 b′, 9 b″, 9 f, 9 e, 9 f′, and 9e′.

Referring to FIG. 16A, FIG. 25, and FIGS. 33A and 33B, the cell groundline 10 a and the cell power line 10 b are formed in the interlayerinsulator 11. While forming the cell ground line 10 a and the cell powerline 10 b, the peripheral power line 10 e, the peripheral ground line 10f and the output signal line 10 g may be formed in the interlayerinsulator 11 of the peripheral circuit region P.

In the embodiments of the present invention, the inverter is depicted inthe drawings as an example of the peripheral circuit, but the peripheralcircuit is not limited to this. That is, the MOS transistors of theperipheral circuit region P can be used as components of the variousperipheral circuits. That is, the peripheral power line 10 e, theperipheral ground line 10 f and the output signal line 10 g are toimplement the inverter as an example of the peripheral circuit, and thePMOS transistor and the NMOS transistor of the peripheral circuit regionP can constitute various peripheral circuits.

The cell ground line 10 a and the cell power line 10 b may be formed tobe substantially parallel to the word line 6 b. The cell ground line 10is formed to cover the ground line contact plugs 9 b′ and 9 b″, and thecell power line 10 b is formed to cover the power line contact plugs 9a′ and 9 a″. The output signal line 10 g is formed to cover the outputsignal line contact plugs 9 e′ and 9 f. The peripheral ground line 10 fis formed to cover the peripheral ground line contact plug 9 f′. Whileforming the output signal line 10 g, the input signal line 10 h which iselectrically connected to the peripheral PMOS gate electrode 23 a′ andthe peripheral NMOS gate electrode 20 c″ may be formed. The input signalline 10 h may be electrically connected to the peripheral PMOS gateelectrode 23 a′ and the peripheral NMOS gate electrode 20 c″ by theinput signal line contact plug. The interlayer insulator 12 is formed onthe semiconductor substrate having the ground lines 10 a and 10 f, thepower lines 10 b and 10 e, the output signal line 10 g, the input signalline 10 h.

Referring to FIG. 16A, FIG. 25, and FIGS. 34A and 34B, the interlayerinsulators 7 e, 9 c, 11, and 12 and the etching stopper layer 7 d areetched to form the first and second contact plugs 13 a′ and 13 a″ whichrespectively contact the drain region T1D of the NMOS transistor T1 andthe drain region T2D of the NMOS transistor T2. The first and secondparallel bit lines 14 are formed on the interlayer insulator 12. Thefirst and second bit lines 14 are formed to cross over the cell groundline 10 a and the cell power line 10 b. The first bit line 14 is formedto cover the bit line contact plug 13 a′, and the second bit line 14 isformed to cover the bit line contact plug 13 a″.

The above described embodiments have been described focusing on thestatic semiconductor memory device, but the peripheral circuit of thepresent invention can be employed in the dynamic semiconductor memorydevice to reduce the layout area size.

As described herein before, the semiconductor memory device and thearrangement method thereof according to the present invention can reducethe whole layout area size because it is possible to stack thetransistors which constitute the peripheral circuit as well as thememory cell array.

Further, the semiconductor memory device and the manufacturing methodthereof according to the present invention can provide the semiconductorintegrated circuits having high integrated memory cells and highperformance peripheral transistors because the memory cell having thethin film transistors is provided in the memory cell array and theperipheral transistors are provided in the peripheral body pattern ofthe single crystal semiconductor structure grown from the semiconductorsubstrate of the peripheral circuit region. That is, stable operationcan be performed by stacking the transistors which constitute the memorycell array and arranging the transistors which constitute the peripheralcircuit on the third layer.

1. An integrated circuit memory device, comprising: a semiconductorsubstrate; a static random access memory (SRAM) cell comprising avertically stacked arrangement of a pair of NMOS access transistors, apair of NMOS pull-down transistors and a pair of PMOS pull-uptransistors, on said semiconductor substrate; and a logic gatecomprising a vertically stacked arrangement of MOS transistors at threelevels, on said semiconductor substrate.
 2. The memory device of claim1, wherein said SRAM cell is disposed in a memory cell portion of saidsemiconductor substrate; and wherein said logic gate is disposed in aperipheral circuit portion of said semiconductor substrate.
 3. Thememory device of claim 2, wherein said logic gate is selected from agroup consisting of inverters, NAND gates and NOR gates.
 4. The memorydevice of claim 1, wherein said logic gate is selected from a groupconsisting of inverters, NAND gates and NOR gates.
 5. The memory deviceof claim 1, wherein said logic gate is an inverter comprising two NMOStransistors connected in parallel and one PMOS transistor.
 6. The memorydevice of claim 1, wherein said logic gate is an inverter comprising atleast one NMOS transistor and at least one PMOS transistor.
 7. Anintegrated circuit memory device, comprising: a semiconductor substrate;a static random access memory (SRAM) cell comprising a verticallystacked arrangement of a pair of NMOS access transistors, a pair of NMOSpull-down transistors and a pair of PMOS pull-up transistors, on saidsemiconductor substrate; and a logic gate comprising a verticallystacked arrangement of MOS transistors at three levels, on saidsemiconductor substrate; wherein said logic gate is an invertercomprising two NMOS transistors connected in parallel and one PMOStransistor; and wherein the two NMOS transistors in the inverter arevertically stacked relative to each other on two of the three levels. 8.The memory device of claim 7, wherein one of the two NMOS transistors isa bulk NMOS transistor.
 9. The memory device of claim 8, wherein thePMOS transistor in the inverter is disposed between the two NMOStransistors.
 10. An integrated circuit memory device, comprising: asemiconductor substrate; a static random access memory (SRAM) cellcomprising a vertically stacked arrangement of a pair of NMOS accesstransistors, a pair of NMOS pull-down transistors and a pair of PMOSpull-up transistors, on said semiconductor substrate; and a logic gatecomprising a vertically stacked arrangement of MOS transistors at threelevels, on said semiconductor substrate; wherein said logic gate is aninverter comprising two PMOS transistors connected in parallel and oneNMOS transistor; and wherein the two PMOS transistors in the inverterare vertically stacked relative to each other on two of the threelevels.
 11. An integrated circuit memory device, comprising: asemiconductor substrate; a static random access memory (SRAM) cellcomprising a vertically stacked arrangement of a pair of NMOS accesstransistors, a pair of NMOS pull-down transistors and a pair of PMOSpull-up transistors, on said semiconductor substrate; and a logic gatecomprising a vertically stacked arrangement of MOS transistors at threelevels, on said semiconductor substrate; wherein said logic gate is aninverter comprising two PMOS transistors connected in parallel and oneNMOS transistor; wherein one of the two PMOS transistors is a bulk PMOStransistor; and wherein the NMOS transistor in the inverter is disposedbetween the two PMOS transistors.
 12. The memory device of claim 11,wherein the NMOS transistor in the inverter is a thin-film transistor.13. A semiconductor device, comprising: a plurality of invertersincluding at least one first pull-up transistor and first pull-downtransistor and inverting and outputting an input signal, respectively;and a plurality of NAND pates including at least two second pull-uptransistor and second pull-down transistor and generating an outputsignal having a high level if at least one of at least two input signalshas a low level, respectively, wherein the at least one first pull-uptransistor and first pull-down transistor and the at least two secondpull-up transistor and second pull-down transistor are stacked andarranged on at least two layers; wherein the first and second pull-uptransistors are PMOS transistors, and the first and second pull-downtransistors are NMOS transistors wherein a transistor to be arranged ona first layer is a bulk transistor, and a transistor to be arranged on asecond or more layer is a thin film transistor; wherein some of thefirst and second pull-up transistors and some of the first and secondpull-down transistors are arranged together on the first layer; andwherein only the first and second pull-up transistors or only the firstand second pull-down transistors are arranged on the second or morelayer.
 14. An integrated circuit memory device, comprising: asemiconductor substrate; a static random access memory (SRAM) cellcomprising a vertically stacked arrangement of a pair of NMOS accesstransistors, a pair of NMOS pull-down transistors and a pair of PMOSpull-up transistors, on said semiconductor substrate; and a logic gatecomprising a vertically stacked arrangement of MOS transistors at threelevels, on said semiconductor substrate; wherein said logic gate is aninverter comprising an NMOS transistor and a PMOS transistor; andwherein the NMOS transistor in the inverter and the PMOS transistor inthe inverter are vertically stacked relative to each other on two of thethree levels.